O-O Classes (still from White Paper)
A class is a software construct that defines the data (state or fields) and methods (behavior) of the specific concrete object instances that are subsequently constructed from that class.
Fields are the data for the class. Methods are the sequences of statements that operate on the data.
Fields are normally specific to an object, that is, every object constructed from the class definition will have its own copy of the field. Such fields are known as instance variables.
Similarly, methods are also normally declared to operate on the instance variables of the class, and are thus known as instance methods.