I'm just starting to learn objective-c and Cocoa here, and I'm a bit puzzled by the use of a * in front of variables. My book doesn't say anything about it, and the Stanford class doesn't either. Tried searching but that didn't give me any clear answers either. So what is the * in front of variables good for, and when do you need it? Also saw a piece of code where someone used ** in front of a variable, was that a typo?