Cocoa and Objective-C Up and Running.

I've read already many book about Objective-C and didn't think that I can find something new in this one. I was wrong. It's really a great book.
For example:
[object method];
[object methodWithInput: inputValue];
Objective-C is a dynamic language, so technically you are not calling a method directly when you use this syntax; you are actually sending a message. Calling a method is basically issuing an order, whereas sending a message is more like making a request.