I am new to XCode, Cocoa, and the lot. I have read through some books, Cocoa Programming for Mac OS X 2nd Edition and Beginning Mac OS X Programming are the main two, but I have yet to really see a book that covers 10.4 and Core Data along with the Data Modeler. I attempted today to write a simple app, a recipe manager with categories, using the Data Modeler to model out the entities. I then dropped an NSBrowser on my window, added a NSTreeController, and set the NSTreeController to "Entity",named Category, and set the Content binding of the NSBrowser to the NSTreeController. I also added two buttons, binding one to canInsertChild and the other to canRemoveChild, and connected them to insertChild and removeChild of NSTreeController. So, I start it up, and I see an empty NSBrowser, but nother seems to work. What am I doing wrong? The next question is: Are there any good books out that cover Core Data. I am also looking for some "Best Practices" books. Primarily I want books covering 10.4, but it looks like there aren't any yet. Oh, forgot to mention I am a Sun Certified Developer in Java 2, so my background is Java/C++/C, but I am trying to learn Cocoa and Objective-C.