Serialization usually refers to the process of converting an abstract datatype to a stream of bytes (You sometimes serialize to text, XML or CSV or other formats as well. The important thing is that it is a simple format that can be read/written without understanding the abstract objects that the data represents). When saving data to a file, or transmitting over a network, you can't just store a MyClass object, you're only able to store bytes. So you need to take all the data necessary to reconstruct your object, and turn that into a sequence of bytes that can be written to the destination device, and at some later point read back and deserialized, reconstructing your object.
