diff --git a/example/main.dart b/example/main.dart
index 3d747d7a..8941432c 100644
--- a/example/main.dart
+++ b/example/main.dart
@@ -12,11 +12,38 @@ main() async {
 
   var app = Angel(logger: Logger('angel_validate'));
   var http = AngelHttp(app);
+  var todos = <Todo>[];
 
+  /// We can combine fields into a form; this is most
+  /// useful when we immediately deserialize the form into
+  /// something else.
   var todoForm = Form(fields: [
-    
+    TextField('text'),
+    BoolField('is_complete'),
   ]);
 
+  /// We can directly use a `Form` to deserialize a
+  /// request body into a `Map<String, dynamic>`.
+  ///
+  /// By calling `deserialize` or `decode`, we can populate
+  /// concrete Dart objects.
+  app.post('/', (req, res) async {
+    var todo = await todoForm.deserialize(req, Todo.fromMap);
+    todos.add(todo);
+    await res.redirect('/');
+  });
+
+  /// You can also use `Field`s to read directly from the
+  /// request, without `as` casts.
+  ///
+  /// In this handler, we read the value of `name` from the query.
+  app.get('/hello', (req, res) async {
+    var nameField = TextField('name');
+    var name = await nameField.getValue(req, query: true);
+    return 'Hello, $name!';
+  });
+
+  /// Simple page displaying a form and some state.
   app.get('/', (req, res) {
     res
       ..contentType = MediaType('text', 'html')
@@ -24,6 +51,12 @@ main() async {
     <!doctype html>
     <html>
       <body>
+        <h1>angel_validate</h1>
+        <ul>
+          ${todos.map((t) {
+        return '<li>${t.text} (isComplete=${t.isComplete})</li>';
+      }).join()}
+        </ul>
         <form method="POST">
           <label for="text">Text:</label>
           <input id="text" name="text">
@@ -31,7 +64,7 @@ main() async {
           <label for="is_complete">Complete?</label>
           <input id="is_complete" name="is_complete" type="checkbox">
           <br>
-          <input type="submit" value="submit">
+          <button type="submit">Add Todo</button>
         </form>
       </body>
     </html>
@@ -48,6 +81,7 @@ main() async {
   };
 
   await http.startServer('127.0.0.1', 3000);
+  print('Listening at ${http.uri}');
 }
 
 class Todo {
diff --git a/lib/src/common_fields.dart b/lib/src/common_fields.dart
index 867466bf..b9c47c27 100644
--- a/lib/src/common_fields.dart
+++ b/lib/src/common_fields.dart
@@ -5,11 +5,17 @@ import 'form_renderer.dart';
 
 /// A [Field] that accepts plain text.
 class TextField extends Field<String> {
-  /// If `true`, then renderers will produce a `<textarea>` element.
+  /// If `true` (default), then renderers will produce a `<textarea>` element.
   final bool isTextArea;
 
+  /// If `true` (default), then the input will be trimmed before validation.
+  final bool trim;
+
   TextField(String name,
-      {String label, bool isRequired = false, this.isTextArea = false})
+      {String label,
+      bool isRequired = true,
+      this.isTextArea = false,
+      this.trim = true})
       : super(name, label: label, isRequired: isRequired);
 
   @override
@@ -17,10 +23,16 @@ class TextField extends Field<String> {
       renderer.visitTextField(this);
 
   @override
-  FutureOr<FieldReadResult<String>> read(RequestContext req) {
-    var value = req.bodyAsMap[name] as String;
+  FutureOr<FieldReadResult<String>> read(
+      Map<String, dynamic> fields, Iterable<UploadedFile> files) {
+    var value = fields[name] as String;
+    if (trim) {
+      value = value?.trim();
+    }
     if (value == null) {
       return null;
+    } else if (trim && value.isEmpty) {
+      return null;
     } else {
       return FieldReadResult.success(value);
     }
@@ -30,7 +42,7 @@ class TextField extends Field<String> {
 /// A [Field] that checks simply for its presence in the given data.
 /// Typically used for checkboxes.
 class BoolField extends Field<bool> {
-  BoolField(String name, {String label, bool isRequired = false})
+  BoolField(String name, {String label, bool isRequired = true})
       : super(name, label: label, isRequired: isRequired);
 
   @override
@@ -38,13 +50,12 @@ class BoolField extends Field<bool> {
       renderer.visitBoolField(this);
 
   @override
-  FutureOr<FieldReadResult<bool>> read(RequestContext req) {
-    if (req.bodyAsMap.containsKey(name)) {
+  FutureOr<FieldReadResult<bool>> read(
+      Map<String, dynamic> fields, Iterable<UploadedFile> files) {
+    if (fields.containsKey(name)) {
       return FieldReadResult.success(true);
-    } else if (!isRequired) {
-      return FieldReadResult.success(false);
     } else {
-      return null;
+      return FieldReadResult.success(false);
     }
   }
 }
diff --git a/lib/src/field.dart b/lib/src/field.dart
index 1ea0b700..3c6b302a 100644
--- a/lib/src/field.dart
+++ b/lib/src/field.dart
@@ -1,6 +1,7 @@
 import 'dart:async';
 import 'package:angel_framework/angel_framework.dart';
 import 'package:matcher/matcher.dart';
+import 'form.dart';
 import 'form_renderer.dart';
 
 /// Holds the result of validating a field.
@@ -37,13 +38,14 @@ abstract class Field<T> {
   /// present, an error will be generated.
   final bool isRequired;
 
-  Field(this.name, {this.label, this.isRequired = false});
+  Field(this.name, {this.label, this.isRequired = true});
 
   /// Reads the value from the request body.
   ///
   /// If it returns `null` and [isRequired] is `true`, an error must
   /// be generated.
-  FutureOr<FieldReadResult<T>> read(RequestContext req);
+  FutureOr<FieldReadResult<T>> read(
+      Map<String, dynamic> fields, Iterable<UploadedFile> files);
 
   /// Accepts a form renderer.
   FutureOr<U> accept<U>(FormRenderer<U> renderer);
@@ -51,6 +53,37 @@ abstract class Field<T> {
   /// Wraps this instance in one that throws an error if any of the
   /// [matchers] fails.
   Field<T> match(Iterable<Matcher> matchers) => _MatchedField(this, matchers);
+
+  /// Calls [read], and returns the retrieve value from the body.
+  ///
+  /// If [query] is `true` (default: `false`), then the value will
+  /// be read from the request `queryParameters` instead.
+  ///
+  /// If there is an error, then an [AngelHttpException] is thrown.
+  /// If a [defaultValue] is provided, it will be returned in case of an
+  /// error or missing value.
+  Future<T> getValue(RequestContext req,
+      {String errorMessage, T defaultValue, bool query = false}) async {
+    var uploadedFiles = <UploadedFile>[];
+    if (req.hasParsedBody || !query) {
+      await req.parseBody();
+      uploadedFiles = req.uploadedFiles;
+    }
+    var result =
+        await read(query ? req.queryParameters : req.bodyAsMap, uploadedFiles);
+    if (result?.isSuccess != true && defaultValue != null) {
+      return defaultValue;
+    } else if (result == null) {
+      errorMessage ??= Form.reportMissingField(name, query: query);
+      throw AngelHttpException.badRequest(message: errorMessage);
+    } else if (!result.isSuccess) {
+      errorMessage ??= result.errors.first;
+      throw AngelHttpException.badRequest(
+          message: errorMessage, errors: result.errors.toList());
+    } else {
+      return result.value;
+    }
+  }
 }
 
 class _MatchedField<T> extends Field<T> {
@@ -66,8 +99,9 @@ class _MatchedField<T> extends Field<T> {
   FutureOr<U> accept<U>(FormRenderer<U> renderer) => inner.accept(renderer);
 
   @override
-  Future<FieldReadResult<T>> read(RequestContext req) async {
-    var result = await inner.read(req);
+  Future<FieldReadResult<T>> read(
+      Map<String, dynamic> fields, Iterable<UploadedFile> files) async {
+    var result = await inner.read(fields, files);
     if (!result.isSuccess) {
       return result;
     } else {
diff --git a/lib/src/form.dart b/lib/src/form.dart
index 6910874e..c76ec7f8 100644
--- a/lib/src/form.dart
+++ b/lib/src/form.dart
@@ -32,6 +32,12 @@ class Form {
       'There were errors in your submission. '
       'Please make sure all fields entered correctly, and submit it again.';
 
+  /// Computes an error message in the case of a missing required field.
+  static String reportMissingField(String fieldName, {bool query = false}) {
+    var type = query ? 'query parameter' : 'field';
+    return 'The $type "$fieldName" is required.';
+  }
+
   Form({this.errorMessage = defaultErrorMessage, Iterable<Field> fields}) {
     fields?.forEach(addField);
   }
@@ -50,20 +56,32 @@ class Form {
   }
 
   /// Deserializes the result of calling [validate].
+  ///
+  /// If [query] is `true` (default: `false`), then the value will
+  /// be read from the request `queryParameters` instead.
   Future<T> deserialize<T>(
-      RequestContext req, T Function(Map<String, dynamic>) f) {
-    return validate(req).then(f);
+      RequestContext req, T Function(Map<String, dynamic>) f,
+      {bool query = false}) {
+    return validate(req, query: query).then(f);
   }
 
   /// Uses the [codec] to [deserialize] the result of calling [validate].
-  Future<T> decode<T>(RequestContext req, Codec<T, Map> codec) {
-    return deserialize(req, codec.decode);
+  ///
+  /// If [query] is `true` (default: `false`), then the value will
+  /// be read from the request `queryParameters` instead.
+  Future<T> decode<T>(RequestContext req, Codec<T, Map> codec,
+      {bool query = false}) {
+    return deserialize(req, codec.decode, query: query);
   }
 
   /// Calls [read], and returns the filtered request body.
   /// If there is even one error, then an [AngelHttpException] is thrown.
-  Future<Map<String, dynamic>> validate(RequestContext req) async {
-    var result = await read(req);
+  ///
+  /// If [query] is `true` (default: `false`), then the value will
+  /// be read from the request `queryParameters` instead.
+  Future<Map<String, dynamic>> validate(RequestContext req,
+      {bool query = false}) async {
+    var result = await read(req, query: query);
     if (!result.isSuccess) {
       throw AngelHttpException.badRequest(
           message: errorMessage, errors: result.errors.toList());
@@ -76,15 +94,24 @@ class Form {
   /// whether valid values were provided for all [fields].
   ///
   /// In most cases, you'll want to use [validate] instead.
-  Future<FieldReadResult<Map<String, dynamic>>> read(RequestContext req) async {
+  ///
+  /// If [query] is `true` (default: `false`), then the value will
+  /// be read from the request `queryParameters` instead.
+  Future<FieldReadResult<Map<String, dynamic>>> read(RequestContext req,
+      {bool query = false}) async {
     var out = <String, dynamic>{};
     var errors = <String>[];
-    await req.parseBody();
+    var uploadedFiles = <UploadedFile>[];
+    if (req.hasParsedBody || !query) {
+      await req.parseBody();
+      uploadedFiles = req.uploadedFiles;
+    }
 
     for (var field in fields) {
-      var result = await field.read(req);
+      var result = await field.read(
+          query ? req.queryParameters : req.bodyAsMap, uploadedFiles);
       if (result == null && field.isRequired) {
-        errors.add('The field "${field.name}" is required.');
+        errors.add(reportMissingField(field.name, query: query));
       } else if (!result.isSuccess) {
         errors.addAll(result.errors);
       } else {
