Duncan Lamont: Play Chords on a Keyboard in 15 Minutes !OUT OF PRINT
Play Chords on a Keyboard in 15 minutesby Duncan Lamont is the book for the non-pianist of any age who wants to start right from the beginning and play the sounds of jazz in literally... 15 minutes!
This book shows actual keyboard diagrams, so even if you don't read music, you still can see which keys to press to play the chords. Also, the chords themselves are related to different well-known tunes, making memorising them dead easy. Here's a sample page: