Here is a an analogy you might use for non-programmers: Computer programs are like instruction manuals to tell the computer what to do. In traditional programs, there is one great book containing all the instructions. In OO programming, in the computer’s virtual universe, there is an instruction book attached to every object that tells the computer what it can do with each object and how. All Dalmatians come with two instruction books, a care and feeding of Dalmatatians, and a generic care and feeding of Dogs. The Cocker Spaniels come with a specialised care and feeding of Cocker Spaniels book, and the exact same book on care and feeding of Dogs. The instructions in the specific books can override the general instructions or add to the general instructions in the Dog book.

For a language to be considered officially object-oriented it needs three features:

• Abstraction — providing some form of classes and objects.
• Inheritance — providing the ability to build new abstractions out of existing ones.
• Run-time polymorphism — providing some form of run-time binding where a different version of the method is used with the decision made which one to use postponed until execution time.

Books

	recommend book⇒Object Design: Roles, Responsibilities, and Collaborations
		paperback
	ISBN10:	0-201-37943-0
	ISBN13:	978-0-201-37943-3
	publisher:	Addison-Wesley
	published:	2002-11-18
	by:	by Rebecca Wirfs-Brock, Alan McKean
Focussing on the issue of who is responsible for what. Wirfs-Brock wrote the 1990 book Designing Object-Oriented Software. This is a more practical than average book of its type.
amazon.ca amazon.com chapters.indigo.ca powells.com amazon.fr barnesandnoble.com amazon.de amazon.co.uk

	recommend book⇒Object-Oriented Methods: Principles and Practice
		hardcover
	ISBN10:	0-201-61913-X
	ISBN13:	978-0-201-61913-3
	publisher:	Addison-Wesley
	published:	2000-12-27
	by:	Ian Graham
A heavyweight book with lots of math. Something you can keep coming back to as you hone your skill.
amazon.ca amazon.com chapters.indigo.ca powells.com amazon.fr barnesandnoble.com amazon.de amazon.co.uk

	recommend book⇒Object Thinking
		paperback
	ISBN10:	0-7356-1965-4
	ISBN13:	978-0-7356-1965-4
	publisher:	Microsoft Press
	published:	2004-03-10
	by:	David West
This is philosophical book about object oriented programming and extreme programming in general rather than how to do it in any particular langugae. This explains the why more than the how.
amazon.ca amazon.com chapters.indigo.ca powells.com amazon.fr barnesandnoble.com amazon.de amazon.co.uk