for learning experience I'm trying to work with arrays. I know how an array works, I have plenty of background with arrays. But NSArrays and MutableArrays are killing me. I create a new project, a regular cocoa one. I make an NSTableView with one column, a button to add to it, and a button to remove from it. I create an NSArrayController, and link it up with the tableview and the buttons, using the built in Array Controller class. But when I try compiling, after properly incorporating the class into my project, I get around 50 errors, saying that my class is incomplete and it lists all these methods that for some reason the class is deciding not to add to itself. When the class was added to the project I saw that it only had three methods. What's wrong? Can someone please either explain how to do it, or simply send via email a project with a tableview, the two buttons and an array, all appropriately linked so I can view it and learn from it? My email address is firstname.lastname@example.org Thanks!