This is a book I just learned about called The Art of the Sketch by Thomas Fluharty, who does caricatures that quite possibly rival those of the legendary Mort Drucker (of Mad Magazine fame). Hmm - that's a powerful statement - not sure I can justify it really, but if anybody can hold a candle to Drucker then Fluharty is the guy!! The book is available through his own website -
The link will take you to the sketchbook in his store, but by all means look around the site a bit - he has most of the sketches posted for free online viewing in his portfolio.
The 2nd book I want to highlight was just recently released as well - it's Figure Drawing for Artists by Steve Huston. I'm very excited to see a book detailing Huston's approach - I've seen tantalizing glimpses of it here and there, most notably in the series of his lectures I posted about some time ago on this blog, which were recorded and posted by one of his students. The book seems to cover the same material and to go into a good deal more depth (I'm only partway into it so far).
He uses a really fascinating method of interspersing gesture and structure as he draws so that each line is one or the other and they're laid out in sequence - gesture line then structure line - gesture line then structure line. He has some vitally important lessons for me to absorb. A few of his images: