This is just a bit of forethought I've just about gone through the Obj-C part of SK twice now (Didn't completely understand some of the material) book but I also have Aaron Hillegass' book. My ultimate goal is to do GUI based work which is why I bought Aaron's book (I can see myself doing some CLI programs) but read SK's Obj-C book on recommendation because I didn't know C. Should I do the Foundation Framework part of the book anyway? Could I use the Foundation Framework and Cocoa together for any arbitrary reason and it wouldn't cause problems? --- In chapter 13 it has information on the underlying features of C, if I do this chapter would I essentially "know" C? As I'm very interested in Operating System Development.