This. This remains the most concise and to-the-point programming book I have -ever- read. It bothers me some that people (myself included) keep writing 900 page programming books when this can do nearly the same in 200.

Once you're done with that, pick up one of the W. Richard Stevens (RIP) books — Advanced Programming in the Unix environment, or Unix Network Programming (Vol i/ii) if you're into networks. They'll teach you the basics of so much operating system stuff (it'll be Unix, but the core concepts will apply to any modern OS) you'll be growing a long unkempt beard and wearing sandals/suspenders in no time.