what is the difference between serializable and marshalbyrefobject in remoting?

In .net Remoting if u want ur class to be participated in remoting it has to inherit from MarshalByRefObject class so that class definition can be passed by reference Where as [seraliazable] attribute is preceded before class that is can be seralized but this is used in conjuction with MarshalByValue class.Because when we pass by value then only we require this attribute