diff --git a/src/R3/Observable.cs b/src/R3/Observable.cs
index 40bc9557..cab4a1f5 100644
--- a/src/R3/Observable.cs
+++ b/src/R3/Observable.cs
@@ -4,7 +4,7 @@
 
 namespace R3;
 
-public abstract class Observable<T> : IObservable<T>
+public abstract class Observable<T>
 {
     [StackTraceHidden, DebuggerStepThrough]
     public IDisposable Subscribe(Observer<T> observer)
@@ -29,14 +29,9 @@ public IDisposable Subscribe(Observer<T> observer)
     }
 
     protected abstract IDisposable SubscribeCore(Observer<T> observer);
-
-    IDisposable IObservable<T>.Subscribe(IObserver<T> observer)
-    {
-        return Subscribe(observer.ToObserver()); // convert IObserver<T> to Observer<T>
-    }
 }
 
-public abstract class Observer<T> : IDisposable, IObserver<T>
+public abstract class Observer<T> : IDisposable
 {
 #if DEBUG
     [Obsolete("Only allow in Event<T>.")]
@@ -122,21 +117,4 @@ public void Dispose()
 
     [StackTraceHidden, DebuggerStepThrough]
     protected virtual void DisposeCore() { }
-
-    // IObserver<T> bridge
-
-    void IObserver<T>.OnNext(T value)
-    {
-        OnNext(value);
-    }
-
-    void IObserver<T>.OnError(Exception error)
-    {
-        OnCompleted(Result.Failure(error));
-    }
-
-    void IObserver<T>.OnCompleted()
-    {
-        OnCompleted(Result.Success);
-    }
 }
diff --git a/src/R3/Operators/ToIObservable.cs b/src/R3/Operators/AsObservable.cs
similarity index 68%
rename from src/R3/Operators/ToIObservable.cs
rename to src/R3/Operators/AsObservable.cs
index 99e796a8..70874939 100644
--- a/src/R3/Operators/ToIObservable.cs
+++ b/src/R3/Operators/AsObservable.cs
@@ -3,20 +3,20 @@
 public static partial class ObservableExtensions
 {
     // TODO: more overload?
-    public static IObservable<T> ToIObservable<T>(this Observable<T> source)
+    public static IObservable<T> AsObservable<T>(this Observable<T> source)
     {
-        return new ToIObservable<T>(source);
+        return new AsObservable<T>(source);
     }
 }
 
-internal sealed class ToIObservable<T>(Observable<T> source) : IObservable<T>
+internal sealed class AsObservable<T>(Observable<T> source) : IObservable<T>
 {
     public IDisposable Subscribe(IObserver<T> observer)
     {
-        return source.Subscribe(new ObserverToobserver(observer));
+        return source.Subscribe(new ObserverToObserver(observer));
     }
 
-    sealed class ObserverToobserver(IObserver<T> observer) : Observer<T>
+    sealed class ObserverToObserver(IObserver<T> observer) : Observer<T>
     {
         protected override void OnNextCore(T value)
         {