I can't say that I know a whole lot about photography, but I'd heard that August Sander was a pioneer in portrait photographs and so I decided to pick up this set. It's a little on the expensive side and I wish the pictures took up the whole page, but the pages are thick and glossy and the quality of the prints is good.
The information in the beginning of the books is sparse--it will tide you over until you research Sander on your own, but it's not definitive by any means.
What I liked most about this set is that it includes such a wide chronology of this artist's work, and you can really feel a progression of this artist as his subjects become more detailed, more interesting, more vibrant. Whether this was an intended aesthetic progression set up by the artist or whether it just shows a change in his prerogatives in photography, I didn't learn from the intros; and, really, I don't think it matters. It's fascinating to see and the subjects are heartbreaking, bizarre, and real.