I've been wandering my way through Adrian Shaughnessy's How To Be a Graphic Designer Without Losing Your Soul over the past couple weeks and have to give it a strong recommendation to all designers, not just graphic as the title limits it to.
The strength of the book really comes from Shaughnessy's ability to frame situations from all the player's viewpoints (student, interviewee, interviewer, freelancer, manager, client, etc.) and shows how to keep proper perspective in those situations. The fact that he has quite a bit of professional success gives weight to the advice he gives and is smart enough not to give definitive answers to problems, even to the point of giving instances that he has ignored his own words of wisdom for better or worse. Definitely worth the $17 at YouWorkForThem.