Basic chess Endings by Reuben Fine.
Endgame Studies
I also hear rumors that there are Chessbase databases of endgame studies. Does anyone know where I might find those?
Harold van der Heijden has one but it is not for free, http://hhdbv.nl/. n9531l regularly consults it to identify posted studies.

Domination in 2,545 Endgame Studies
https://www.amazon.com/dp/0923891870/
There seems to be an android app for that,and free too
https://play.google.com/store/apps/details?id=com.chessking.android.learn.endgamestudies
I have one convekta course with the same name,with just basic ending knowledge solving endgame studies are rewarding.

chess2Knights wrote:
Not sure what you mean?
Endgame studies are typically composed positions that are solved for training or recreation. They are basically a form of chess puzzle although they often resemble plausible game situations far more than other types of puzzles. The book silentknighte5 mentioned, Domination in 2,545 Endgame Studies, is a classic of the genre although the studies there are all based on the theme of domination. I'm hoping to identify good sources of studies on other themes as well.
Silmans Endgame Course and Basic Chess Endings are great books on the endgame. Neither of them is a book of endgame studies.

Besides the Kasparyan book (comment #7) there's also 1234 Modern End-Game Studies by Sutherland and Lommer. If you want a historical perspective, the 1851 book Chess Studies or Endings of Games by Kling and Horwitz has some good studies. You can buy an original copy of the 1851 book in good condition for about $2500 on Amazon, or you can do like I did and buy a facsimile copy from India for $26.

Here's a study from the Kling and Horwitz book with a theme Arisktotle will recognize.
White to play and win

Another one I have is "360 Brilliant and Instructive End Games" by A.A. Troitsky, Dover 1968. It has quite a few nice studies, but also a rather surprising number of unsound ones and faulty solutions. It might be worthwhile endgame training to go through this book and try to distinguish the sound and unsound studies.
The two books above are the same, but to save printing costs a four page solution to one of the studies and the sixty page supplement on two knights v. pawn were excised from "360 Brilliant and Instructive End Games". Many of the studies end in two knights v. pawn and the solutions then simply say, "and wins", so which you get would probably depend on whether you intend looking at the solutions.
Can anyone recommend good books of endgame studies?
I also hear rumors that there are Chessbase databases of endgame studies. Does anyone know where I might find those?