A lot of folks have heard about Scott Robertson's "How to Draw" - it's basically a classic at this point, and deservedly so. It's also a book that a lot of people struggle with, for the simple reason that they expect it to be a manual or a lesson plan explaining, well... how to draw. It's a reasonable assumption, but I've found that book to be more of a reference book - like an encyclopedia for perspective problems, more useful to people who already have a good basis in perspective.

Sketching: The Basics is a far better choice for beginners. It's more digestible, and while it introduces a lot of similar concepts, it does so in a manner more suited to those earlier in their studies.