The BCL includes support for serializing arbitrary object graphs to and from a stream. This serialization can store and transmit complex data structures via files or the network. The default serializers provide binary and XML-based formatting but can be extended with user-defined formatters.

For more information, see the following namespaces:

System.Runtime.Serialization
System.Runtime.Serialization.Formatters
System.Runtime.Serialization.Formatters.Soap
System.Runtime.Serialization.Formatters.Binary

Important types in other namespaces include:

System.NonSerializedAttribute 
System.SerializableAttribute