How does Windows Hibernation works

Out of curiosity, I was looking for an article/documentation on "how windows hibernate option work", i.e. when one selects "Hibernate" option in windows shutdown dialog. The reply I got from some sources was that, its mere serialization of memory and registers.

Pardon me if I am wrong here. If windows could serialize any applications, process or objects regardless of whether its serializable or non-serializable, how come .NET limits serializable objects to those with [Serializable] attribute or ISerializable interface?