diff --git a/HotwiredBooks.sln.DotSettings.user b/HotwiredBooks.sln.DotSettings.user
index 44bb357..0a6041a 100644
--- a/HotwiredBooks.sln.DotSettings.user
+++ b/HotwiredBooks.sln.DotSettings.user
@@ -1,8 +1,11 @@
 <wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:String x:Key="/Default/Environment/AssemblyExplorer/XmlDocument/@EntryValue">&lt;AssemblyExplorer&gt;
+  &lt;Assembly Path="/home/andreas/.nuget/packages/erroror/1.3.0/lib/net6.0/ErrorOr.dll" /&gt;
+&lt;/AssemblyExplorer&gt;</s:String>
 	
-	<s:String x:Key="/Default/Environment/UnitTesting/UnitTestSessionStore/Sessions/=56f95705_002D69f0_002D4d78_002D9fec_002Db8596a7edfd4/@EntryIndexedValue">&lt;SessionState ContinuousTestingMode="0" Name="Create_inserts_value_into_repository" xmlns="urn:schemas-jetbrains-com:jetbrains-ut-session"&gt;
+	<s:String x:Key="/Default/Environment/UnitTesting/UnitTestSessionStore/Sessions/=56f95705_002D69f0_002D4d78_002D9fec_002Db8596a7edfd4/@EntryIndexedValue">&lt;SessionState ContinuousTestingMode="0" IsActive="True" Name="Create_inserts_value_into_repository" xmlns="urn:schemas-jetbrains-com:jetbrains-ut-session"&gt;
   &lt;Project Location="/home/andreas/code/HotwiredBooks/HotwiredBooksTests" Presentation="&amp;lt;HotwiredBooksTests&amp;gt;" /&gt;
 &lt;/SessionState&gt;</s:String>
-	<s:String x:Key="/Default/Environment/UnitTesting/UnitTestSessionStore/Sessions/=7a5365d0_002Db616_002D4d4b_002D83e3_002Df6bda9b641db/@EntryIndexedValue">&lt;SessionState ContinuousTestingMode="0" IsActive="True" Name="Create_inserts_value_into_repository #2" xmlns="urn:schemas-jetbrains-com:jetbrains-ut-session"&gt;
+	<s:String x:Key="/Default/Environment/UnitTesting/UnitTestSessionStore/Sessions/=7a5365d0_002Db616_002D4d4b_002D83e3_002Df6bda9b641db/@EntryIndexedValue">&lt;SessionState ContinuousTestingMode="0" Name="Create_inserts_value_into_repository #2" xmlns="urn:schemas-jetbrains-com:jetbrains-ut-session"&gt;
   &lt;Project Location="/home/andreas/code/HotwiredBooks/HotwiredBooksTests" Presentation="&amp;lt;HotwiredBooksTests&amp;gt;" /&gt;
 &lt;/SessionState&gt;</s:String></wpf:ResourceDictionary>
\ No newline at end of file
diff --git a/HotwiredBooks/Components/IBooksRepository.cs b/HotwiredBooks/Components/IBooksRepository.cs
index 8ea9555..21248a1 100644
--- a/HotwiredBooks/Components/IBooksRepository.cs
+++ b/HotwiredBooks/Components/IBooksRepository.cs
@@ -1,13 +1,13 @@
 using HotwiredBooks.Models;
-using MonadicBits;
+using ErrorOr;
 
 namespace HotwiredBooks.Components;
 
 public interface IBooksRepository
 {
-    Task<Maybe<Book>> Lookup(Guid id);
+    Task<ErrorOr<Book>> Lookup(Guid id);
     Task<IEnumerable<Book>> All();
-    Task<Maybe<Book>> Create(string title, string author);
-    Task<Maybe<Book>> Update(Book book);
-    Task<Maybe<Book>> Delete(Book book);
+    Task<ErrorOr<Book>> Create(string title, string author);
+    Task<ErrorOr<Book>> Update(Book book);
+    Task<ErrorOr<Book>> Delete(Book book);
 }
diff --git a/HotwiredBooks/Components/MemoryBasedBooksRepository.cs b/HotwiredBooks/Components/MemoryBasedBooksRepository.cs
index 6487a86..2176cec 100644
--- a/HotwiredBooks/Components/MemoryBasedBooksRepository.cs
+++ b/HotwiredBooks/Components/MemoryBasedBooksRepository.cs
@@ -1,12 +1,12 @@
 using System.Collections.Concurrent;
 using bridgefield.FoundationalBits;
 using HotwiredBooks.Models;
-using MonadicBits;
+using ErrorOr;
+using ErrorOr.Extensions;
+using HotwiredBooks.Extensions;
 
 namespace HotwiredBooks.Components;
 
-using static Functional;
-
 internal interface IBooksCommand;
 
 internal sealed record Create(string Title, string Author, DateTime CreatedAt) : IBooksCommand;
@@ -17,44 +17,45 @@ internal sealed record Delete(Book Book) : IBooksCommand;
 
 public sealed class MemoryBasedBooksRepository : IBooksRepository
 {
-    private readonly IAgent<IBooksCommand, Maybe<Book>> agent;
+    private readonly IAgent<IBooksCommand, ErrorOr<Book>> agent;
     private readonly ConcurrentDictionary<Guid, Book> books = new(InitialBooks());
 
     public MemoryBasedBooksRepository() =>
-        agent = Agent.Start<ConcurrentDictionary<Guid, Book>, IBooksCommand, Maybe<Book>>(
+        agent = Agent.Start<ConcurrentDictionary<Guid, Book>, IBooksCommand, ErrorOr<Book>>(
             books,
             (current, command) => command switch
             {
-                Create create => Task.FromResult((current,
-                    from book in new Book(Guid.NewGuid(), create.Title, create.Author, create.CreatedAt).Just()
-                    from createdBook in current.TryAdd(book.Id, book) ? book.Just() : Nothing
-                    select createdBook)),
-                Delete delete => Task.FromResult((current,
-                    current.TryRemove(delete.Book.Id, out var deletedBook) ? deletedBook.Just() : Nothing)),
+                Create create => (current,
+                    from book in new Book(Guid.NewGuid(), create.Title, create.Author, create.CreatedAt).Success()
+                    from createdBook in current.TryAdd(book.Id, book) ? book.Success() : ErrorOr<Book>.From([Error.Failure()])
+                    select createdBook).AsTask(),
+                Delete delete => (current,
+                    current.TryRemove(delete.Book.Id, out var deletedBook) ? deletedBook.Success() : ErrorOr<Book>.From(
+                        [Error.Failure()])).AsTask(),
                 Update update => Task.FromResult((current,
                     from currentBook in current.TryGetValue(update.Book.Id, out var currentValue)
-                        ? currentValue.Just()
-                        : Nothing
+                        ? currentValue.Success()
+                        : ErrorOr<Book>.From([Error.Failure()])
                     from updatedBook in current.TryUpdate(update.Book.Id, update.Book, currentBook)
-                        ? update.Book.Just()
-                        : Nothing
+                        ? update.Book.Success()
+                        : ErrorOr<Book>.From([Error.Failure()])
                     select updatedBook)),
                 _ => throw new ArgumentOutOfRangeException(nameof(command))
             });
 
-    public Task<Maybe<Book>> Lookup(Guid id) =>
-        Task.FromResult(books.TryGetValue(id, out var book) ? book.Just() : Nothing);
+    public Task<ErrorOr<Book>> Lookup(Guid id) =>
+        Task.FromResult(books.TryGetValue(id, out var book) ? ErrorOrFactory.From(book) : Error.NotFound());
 
     public Task<IEnumerable<Book>> All() =>
         Task.FromResult<IEnumerable<Book>>(books.Values);
 
-    public Task<Maybe<Book>> Create(string title, string author) =>
+    public Task<ErrorOr<Book>> Create(string title, string author) =>
         agent.Tell(new Create(title, author, DateTime.Now));
 
-    public Task<Maybe<Book>> Update(Book book) =>
+    public Task<ErrorOr<Book>> Update(Book book) =>
         agent.Tell(new Update(book));
 
-    public Task<Maybe<Book>> Delete(Book book) =>
+    public Task<ErrorOr<Book>> Delete(Book book) =>
         agent.Tell(new Delete(book));
 
     private static IEnumerable<KeyValuePair<Guid, Book>> InitialBooks()
diff --git a/HotwiredBooks/Controllers/BooksController.cs b/HotwiredBooks/Controllers/BooksController.cs
index 9291af5..205226c 100644
--- a/HotwiredBooks/Controllers/BooksController.cs
+++ b/HotwiredBooks/Controllers/BooksController.cs
@@ -1,3 +1,5 @@
+using ErrorOr;
+using ErrorOr.Extensions;
 using HotwiredBooks.Attributes;
 using HotwiredBooks.Components;
 using HotwiredBooks.Extensions;
@@ -5,7 +7,6 @@
 using HotwiredBooks.ViewModels;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
-using MonadicBits;
 
 namespace HotwiredBooks.Controllers;
 
@@ -32,7 +33,7 @@ from formData in ParseFormData(collection)
             from book in booksRepository.Create(formData.Title, formData.Author)
             select book
         )
-        .MapAsync<Book, IActionResult>(async book =>
+        .Select<Book, IActionResult>(async book =>
             View(new BooksCreateViewModel(book, (await booksRepository.All()).Count())))
         .OrElse(StatusCode(500, "An unexpected error occurred on the server."));
 
@@ -40,7 +41,7 @@ select book
     public Task<IActionResult> Edit(Guid id) =>
         booksRepository
             .Lookup(id)
-            .MapAsync<Book, IActionResult>(book => View(new BooksEditViewModel(book)))
+            .Select<Book, IActionResult>(book => View(new BooksEditViewModel(book)))
             .OrElse(StatusCode(500, "An unexpected error occurred on the server."));
 
     [HttpPatch, HttpPut]
@@ -58,7 +59,7 @@ book with
             )
             select updatedBook
         )
-        .MapAsync(book => ViewComponentRenderer.RenderAsync("Book", new BooksEditViewModel(book)))
+        .Select(book => ViewComponentRenderer.RenderAsync("Book", new BooksEditViewModel(book)))
         .OrElse(StatusCode(500, "An unexpected error occurred on the server."));
 
     [HttpPost]
@@ -67,15 +68,15 @@ select updatedBook
     public Task<IActionResult> Delete(Guid id) =>
         booksRepository
             .Lookup(id)
-            .BindAsync(booksRepository.Delete)
-            .MapAsync<Book, IActionResult>(async book =>
+            .SelectMany(booksRepository.Delete)
+            .Select<Book, IActionResult>(async book =>
                 View(new BooksDeleteViewModel(book, (await booksRepository.All()).Count())))
             .OrElse(StatusCode(500, "An unexpected error occurred on the server."));
 
-    private static Task<Maybe<FormData>> ParseFormData(IFormCollection collection) =>
-        Task.FromResult(
-            from title in collection.JustGetValue("title")
-            from author in collection.JustGetValue("author")
-            select new FormData(title, author)
-        );
+    private static Task<ErrorOr<FormData>> ParseFormData(IFormCollection collection) =>
+    (
+        from title in collection.JustGetValue("title")
+        from author in collection.JustGetValue("author")
+        select new FormData(title, author)
+    ).AsTask();
 }
diff --git a/HotwiredBooks/Extensions/AsyncExtensions.cs b/HotwiredBooks/Extensions/AsyncExtensions.cs
new file mode 100644
index 0000000..9f6ea81
--- /dev/null
+++ b/HotwiredBooks/Extensions/AsyncExtensions.cs
@@ -0,0 +1,7 @@
+namespace HotwiredBooks.Extensions;
+
+public static class AsyncExtensions
+{
+    public static Task<T> AsTask<T>(this T value) =>
+        Task.FromResult(value);
+}
diff --git a/HotwiredBooks/Extensions/ErrorOrExtensions.cs b/HotwiredBooks/Extensions/ErrorOrExtensions.cs
new file mode 100644
index 0000000..2c910b0
--- /dev/null
+++ b/HotwiredBooks/Extensions/ErrorOrExtensions.cs
@@ -0,0 +1,9 @@
+using ErrorOr;
+
+namespace HotwiredBooks.Extensions;
+
+public static class ErrorOrExtensions
+{
+    public static ErrorOr<T> Success<T>(this T value) =>
+        ErrorOrFactory.From(value);
+}
diff --git a/HotwiredBooks/Extensions/FunctionalExtensions.cs b/HotwiredBooks/Extensions/FunctionalExtensions.cs
index f202ff4..300b68c 100644
--- a/HotwiredBooks/Extensions/FunctionalExtensions.cs
+++ b/HotwiredBooks/Extensions/FunctionalExtensions.cs
@@ -1,26 +1,27 @@
 using Microsoft.Extensions.Primitives;
-using MonadicBits;
+using ErrorOr;
 
 namespace HotwiredBooks.Extensions;
 
-using static Functional;
-
 public static class FunctionalExtensions
 {
-    public static Maybe<T> ToMaybe<T>(this T value) => value?.Just() ?? Nothing;
+    public static ErrorOr<T> ToErrorOr<T>(this T value) =>
+        value is not null ? ErrorOrFactory.From(value) : ErrorOr<T>.From([Error.Failure()]);
 
-    public static Maybe<StringValues> JustGetValue(this IFormCollection collection, string key) =>
-        collection.TryGetValue(key, out var value) ? value.Just() : Nothing;
+    public static ErrorOr<StringValues> JustGetValue(this IFormCollection collection, string key) =>
+        collection.TryGetValue(key, out var value)
+            ? ErrorOrFactory.From(value)
+            : ErrorOr<StringValues>.From([Error.NotFound()]);
 
-    public static T OrElse<T>(this Maybe<T> maybe, T orElse) =>
-        maybe.Match(value => value, () => orElse);
+    public static T OrElse<T>(this ErrorOr<T> maybe, T orElse) =>
+        maybe.Match(value => value, _ => orElse);
 
-    public static T OrElse<T>(this Maybe<T> maybe, Func<T> orElse) =>
-        maybe.Match(value => value, orElse);
+    public static T OrElse<T>(this ErrorOr<T> maybe, Func<T> orElse) =>
+        maybe.Match(value => value, _ => orElse());
 
-    public static async Task<T> OrElse<T>(this Task<Maybe<T>> maybe, Func<T> orElse) =>
-        (await maybe).Match(value => value, orElse);
+    public static async Task<T> OrElse<T>(this Task<ErrorOr<T>> maybe, Func<T> orElse) =>
+        (await maybe).Match(value => value, _ => orElse());
 
-    public static async Task<T> OrElse<T>(this Task<Maybe<T>> maybe, T orElse) =>
-        (await maybe).Match(value => value, () => orElse);
+    public static async Task<T> OrElse<T>(this Task<ErrorOr<T>> maybe, T orElse) =>
+        (await maybe).Match(value => value, _ => orElse);
 }
diff --git a/HotwiredBooks/Extensions/HtmlHelperExtensions.cs b/HotwiredBooks/Extensions/HtmlHelperExtensions.cs
index 395d1cc..0d94575 100644
--- a/HotwiredBooks/Extensions/HtmlHelperExtensions.cs
+++ b/HotwiredBooks/Extensions/HtmlHelperExtensions.cs
@@ -1,7 +1,7 @@
 using System.Reflection;
+using ErrorOr.Extensions;
 using Humanizer;
 using Microsoft.AspNetCore.Mvc.Rendering;
-using MonadicBits;
 
 namespace HotwiredBooks.Extensions;
 
@@ -12,12 +12,12 @@ public static class HtmlHelperExtensions
 
     public static string DomId(this IHtmlHelper htmlHelper, object @object, string prefix = null) =>
     (
-        from property in @object.GetType().GetProperty("Id").ToMaybe()
-        from value in property.GetValue(@object).ToMaybe()
+        from property in @object.GetType().GetProperty("Id").ToErrorOr()
+        from value in property.GetValue(@object).ToErrorOr()
         select value.ToString()
     ).Match(
         id => $"{DomClass(htmlHelper, @object, prefix)}{Join}{id}",
-        () => DomClass(htmlHelper, @object, prefix ?? New)
+        _ => DomClass(htmlHelper, @object, prefix ?? New)
     );
 
     public static string DomClass(this IHtmlHelper _, object objectOrType, string prefix = null)
diff --git a/HotwiredBooks/HotwiredBooks.csproj b/HotwiredBooks/HotwiredBooks.csproj
index d9f8ba2..d768915 100644
--- a/HotwiredBooks/HotwiredBooks.csproj
+++ b/HotwiredBooks/HotwiredBooks.csproj
@@ -8,7 +8,8 @@
 
     <ItemGroup>
       <PackageReference Include="bridgefield.FoundationalBits" Version="0.1.2" />
-      <PackageReference Include="bridgefield.MonadicBits" Version="0.5.1" />
+      <PackageReference Include="ErrorOr" Version="1.3.0" />
+      <PackageReference Include="ErrorOr.Extensions" Version="1.0.0" />
       <PackageReference Include="Humanizer" Version="2.14.1" />
       <PackageReference Include="System.Reactive" Version="6.0.0" />
     </ItemGroup>
diff --git a/HotwiredBooks/ViewComponents/BookFormViewComponent.cs b/HotwiredBooks/ViewComponents/BookFormViewComponent.cs
index 7f2f8ea..c76510f 100644
--- a/HotwiredBooks/ViewComponents/BookFormViewComponent.cs
+++ b/HotwiredBooks/ViewComponents/BookFormViewComponent.cs
@@ -1,11 +1,11 @@
 using HotwiredBooks.Models;
 using HotwiredBooks.ViewModels;
 using Microsoft.AspNetCore.Mvc;
-using MonadicBits;
+using ErrorOr;
 
 namespace HotwiredBooks.ViewComponents;
 
 public sealed class BookFormViewComponent : ViewComponent
 {
-    public IViewComponentResult Invoke(Maybe<Book> book) => View(new BookFormViewModel(book));
+    public IViewComponentResult Invoke(ErrorOr<Book> book) => View(new BookFormViewModel(book));
 }
diff --git a/HotwiredBooks/ViewModels/BookFormViewModel.cs b/HotwiredBooks/ViewModels/BookFormViewModel.cs
index 7343897..8fb3628 100644
--- a/HotwiredBooks/ViewModels/BookFormViewModel.cs
+++ b/HotwiredBooks/ViewModels/BookFormViewModel.cs
@@ -1,6 +1,6 @@
 using HotwiredBooks.Models;
-using MonadicBits;
+using ErrorOr;
 
 namespace HotwiredBooks.ViewModels;
 
-public sealed record BookFormViewModel(Maybe<Book> Book);
+public sealed record BookFormViewModel(ErrorOr<Book> Book);
diff --git a/HotwiredBooks/Views/Books/Edit.cshtml b/HotwiredBooks/Views/Books/Edit.cshtml
index 98dc2f2..c501454 100644
--- a/HotwiredBooks/Views/Books/Edit.cshtml
+++ b/HotwiredBooks/Views/Books/Edit.cshtml
@@ -1,10 +1,11 @@
 @using HotwiredBooks.Extensions
-@using MonadicBits
+@using HotwiredBooks.TagHelpers
+@using HotwiredBooks.ViewComponents
 @model HotwiredBooks.ViewModels.BooksEditViewModel
 @{
     Layout = null;
 }
 
 <turbo-frame id="@Html.DomId(Model.Book)">
-    <vc:book-form book="@Model.Book.Just()"/>
+    <vc:book-form book="@Model.Book.Success()"/>
 </turbo-frame>
diff --git a/HotwiredBooks/Views/Shared/Components/BookForm/Default.cshtml b/HotwiredBooks/Views/Shared/Components/BookForm/Default.cshtml
index da2b05b..8f15fac 100644
--- a/HotwiredBooks/Views/Shared/Components/BookForm/Default.cshtml
+++ b/HotwiredBooks/Views/Shared/Components/BookForm/Default.cshtml
@@ -1,11 +1,12 @@
+@using ErrorOr.Extensions
 @model HotwiredBooks.ViewModels.BookFormViewModel
 
 @{
-    var id = Model.Book.Map(book => book.Id).Match(id => id.ToString(), () => string.Empty);
-    var action = Model.Book.Match(_ => "Update", () => "Create");
-    var method = Model.Book.Match(_ => "put", () => "post");
-    var title = Model.Book.Map(book => book.Title).Match(title => title, () => string.Empty);
-    var author = Model.Book.Map(book => book.Author).Match(author => author, () => string.Empty);
+    var id = Model.Book.Select(book => book.Id).Match(id => id.ToString(), _ => string.Empty);
+    var action = Model.Book.Match(_ => "Update", _ => "Create");
+    var method = Model.Book.Match(_ => "put", _ => "post");
+    var title = Model.Book.Select(book => book.Title).Match(title => title, _ => string.Empty);
+    var author = Model.Book.Select(book => book.Author).Match(author => author, _ => string.Empty);
 }
 
 <form asp-controller="Books"
diff --git a/HotwiredBooksTests/MemoryBasedBookRepositoryTests.cs b/HotwiredBooksTests/MemoryBasedBookRepositoryTests.cs
index f799dc8..7e11b82 100644
--- a/HotwiredBooksTests/MemoryBasedBookRepositoryTests.cs
+++ b/HotwiredBooksTests/MemoryBasedBookRepositoryTests.cs
@@ -1,5 +1,5 @@
+using ErrorOr.Extensions;
 using HotwiredBooks.Components;
-using MonadicBits;
 
 namespace HotwiredBooksTests;
 
@@ -13,21 +13,21 @@ public static async Task Create_inserts_value_into_repository()
         const string title = "ABC";
         const string author = "DEF";
 
-        var maybe = await repository.Create(title, author);
-        maybe.Match(book => Assert.Multiple(() =>
+        var book = await repository.Create(title, author);
+        book.Switch(b => Assert.Multiple(() =>
             {
-                Assert.That(book.Title, Is.EqualTo(title));
-                Assert.That(book.Author, Is.EqualTo(author));
-                Assert.That(book.Id, Is.Not.EqualTo(new Guid()));
+                Assert.That(b.Title, Is.EqualTo(title));
+                Assert.That(b.Author, Is.EqualTo(author));
+                Assert.That(b.Id, Is.Not.EqualTo(new Guid()));
             }),
-            Assert.Fail
+            _ => Assert.Fail()
         );
 
         var areEqual =
-            from created in Task.FromResult(maybe)
+            from created in Task.FromResult(book)
             from read in repository.Lookup(created.Id)
             select created == read;
 
-        (await areEqual).Match(Assert.True, Assert.Fail);
+        (await areEqual).Switch(Assert.True, _ => Assert.Fail());
     }
 }