Update README

README.md

@@ -1180,7 +1180,7 @@ class FetchMusicsTests: XCTestCase {
 #### [AtomScope](https://ra1028.github.io/swiftui-atom-properties/documentation/atoms/atomscope)
 
 `AtomScope` allows you to monitor changes or override atoms used in descendant views. Unlike `AtomRoot`, they affect only those in scope.  
-See the [Override](#override) and [Debugging](#debugging) sections for specific uses.  
+See the [Override Atoms](#override-atoms) and [Debugging](#debugging) sections for specific uses.  
 
 ```swift
 AtomScope {
@@ -1219,7 +1219,65 @@ struct NewsView: View {
 
 ### Techniques
 
-#### Override
+#### Scoped Atoms
+
+This library is designed with the shared state as a single source of truth first principle, but also the state can be scoped depending on the intended use.  
+Scoped atoms store their state in the nearest [AtomScope](#atomscope) in the ancestor of the view in which the atom is used, and their state is not shared outside the scope. `Scoped` is the attribute for that feature.  
+
+```swift
+struct TextInputAtom: StateAtom, Scoped Hashable {
+    func defaultValue(context: Context) -> String {
+        ""
+    }
+}
+
+struct TextInputView: View {
+    @Watch(TextInputAtom())
+    ...
+}
+
+VStack {
+    // The following two TextInputView don't share TextInputAtom state.
+
+    AtomScope {
+        TextInputView()
+    }
+
+    AtomScope {
+        TextInputView()
+    }
+}
+```
+
+When multiple `AtomScope`s are nested, and you want to store and share an atom state in the particular scope, it is able to define a scope ID which is to find a matching scope.  
+
+```swift
+struct TextScopeID: Hashable {}
+
+struct TextInputAtom: StateAtom, Scoped Hashable {
+    var scopeID: TextScopeID {
+        TextScopeID()
+    }
+
+    func defaultValue(context: Context) -> String {
+        ""
+    }
+}
+
+AtomScope(id: TextScopeID()) {
+    TextInputView()
+
+    AtomScope {
+        // Shares TextInputAtom state with the TextInputView placed in the parent scope.
+        TextInputView()
+    }
+}
+```
+
+This is also useful when multiple identical screens are stacked and each has isolated states such as user inputs.  
+Note that other atoms that depend on the scoped atom will be in a shared state and must be given `Scoped` attribute as well in order to scope them as well.  
+
+#### Override Atoms
 
 Overriding an atom in [AtomRoot](#atomroot) or [AtomScope](#atomscope) overwrites its value when used in the descendant views, which is useful for dependency injection or swapping state in a particular view.  
 
@@ -1247,7 +1305,9 @@ var body: some {
 }
 ```
 
-See [Testing](#testing) section for details on dependency injection on unit tests.
+Note also that overridden atoms will automatically be scoped to the `AtomScope`, but other atoms that depend on them will be in a shared state and must be given `Scoped` attribute (See also: [Scoped Atoms](#scoped-atoms)) in order to scope them as well.  
+
+See [Testing](#testing) section for details on dependency injection on unit tests.  
 
 #### Testing