It's nearly impossible to find the right book for children. For example, MacEnulty's The Chess Kid's Book of King and Pawn Endgame looks very well written to me, but it received terrible reviews on amazon.com.
Maybe Seirawan's Winning Chess Endings ? Not too much theory, pretty good explanations.
Under no circumstances should Fine's Basic Chess Endings be given to kids. A 500+ page brick, small print, hard to read.
I am looking for a book for children (ages 10 to 12) on endgames (or that includes a good section on endgames). Any suggestions would be most welcome. Thank you.