This is a small inexpensive book of "White to move and win" puzzles with very few pieces on the board. Endgame puzzles... although they really are not at all endgame 'studies' but simply tactics as might occur in an endgame. Very many of these puzzles involve taking away squares from enemy pieces. This book changed how I look for tactical opportunities. Probably did more  practically for my rating than any other single book. But it doesn't purport to teach anything. It's just 111 doable puzzles. Hey, it's one of the few chessbooks I ever finished, cover to cover. Great book for a beginner who wants to sharpen tactics. 

buy this used and do not pay more than $3 for this book! It's full of fun, famous, games and amusing chess anecdotes and description of famous personalities all with Reinfeld and Chernev's seriously overcooked commentary and annotations. Great fun. It's in descriptive notation (which absolutely destoys a book for me now, despite my having grown up using descriptive.) It was published in 1949 so it's all about the great era of European Chess from roughly 1850 to 1950, just prior to the Soviet dominance (Fischer excepted) of the next 50 years.  Worth a look for someone who wants to get some chess history, fun games, corny unfunny chess cartoons, and has three dollars, max, to spend. 

I have to post my objections to the AA Troitzky book above. I got ahold of this when I was in my tender developmental stage of chess development & learning. I thought that winning an endgame had more to do with cooking up some complicated and brilliant lengthy combination than simply following a plan that more or less follows from the position you arived at from all the earlier stuff your game. While these compositions are impressive, their practical application is dubious.

This book has given me years of pleasure, also only in descriptive afaik.

Hm, hard to agree with a lot of these being "little-known", but...

I nominate the following.  Despite being compiled/edited by a dingus, it has a lot of interesting material from some very good players indeed (it's also where I first came across that unbelievable Kavalek B vs 2 R's game):

I also found this quite good (way back when):

I can't believe people are adding Pandolfini and Keene books to the thread!

Hey, I said the guy was a dink (but the book isn't actually by him, and it's very good indeed).

Most of the stuff with Keene's name probably isn't by him.

Yeah, I'll bet it's all David Levy's doing.

Lol. I not only added Pandolfini, but Reinfeld (who is imho just dreadful) ...

 but I swear that particular Pandolfini book (which has almost zero text except a brief introduction) is great. As for putting the Reinfeld book on the list... call it a failed troll attempt 

Well, the real oddity is the "little-known" designation.

Great might be pushing it, but here's another little known Pandolfini book that's pretty good.

http://www.amazon.com/RUSSIAN-CHESS-Fireside-Chess-Library/dp/0671619845/ref=la_B000APJ6YQ_1_5?ie=UTF8&qid=1350170006&sr=1-5

Keene's early books wern't bad. The one on Nimzowitch is actually good, and even one on 78 World championship reasonable. In that last one  broke agreement with Korchnoi by doing a book at all, and spent more effort on it, than being his second.