What is the difference between methods that begin with + and -?

Developers are allowed to call [super dealloc] in ARC.

What happens when you call retain on an object?

How can you declare a method, that can be set as the action to be performed on various events?

What does a CAEmitterCell do?

How do you free an object?

What's the difference between an array and a set?

What is this a declaration of? int(^foo)(int);

What are categories used for?

If you want to store a small amount of information (e.g., user settings), whats the best, built-in way to go?

What is an enums base type for the code below? typedef enum { Foo1, Foo2} Foo;