
They're AWESOME.
Cartooning The Head And Figure and Drawing The Head And Figure are, simply stated, replete with instructional tips. Every page is crowded with examples, step-by-step instructions, diagrams or just plain practical wisdom. Next to these books, even the best modern drawing instruction books look sparse.
The trouble is, it's easy to pick these up while browsing and dismiss them outright, because the style of the drawings is quite outdated (they were written in the 1960s). I know this to be true because I almost gave them a pass, until I stopped and looked at Cartooning a second time and noticed how freaking dense it is. Styles may change, but

'Course, Ol' Jack may not have agreed with me on the "millions of years" thing. Seems he didn't hold much truck with such nonsense.
Anyway, yeah. These books are good.
...
...
...seems like I ought to have more to say, but...I guess not.