When you find books on the subject you're interested in, look through them all. There are a lot of very good books on programming, but even more awful ones. Look for a book that looks readable and matches your style. However, try to get as many relevant books as you can. It's almost always better to have as many books on programming as possible.
Every book covers different topics and explains some things better than others.
When you need to use a new system call, owning more books means you'll be more likely to have a book which explains that command well. Also, reading through programming books is a great way to be exposed to new system capabilites you may not have been aware of. Finally, people often ask what the best books are for learning how to program Windows and the Macintosh. Both books are excellent and chock-full of programming goodness. When planning your program, you will need to figure out how you want your interface to look and work, and you will need to determine, for the most part, what your program's feature set will be.