Current Learning Science, from Alston Mabry
I happen to be working in this area the last few years, and I am sold on the insights from current learning science.
Very useful and practical.
This book is an excellent summary by some of the leading researchers:
"Make it Stick: The Science of Successful Learning"
Leo Jia writes:
Spaced repetition of concepts from both directions are the most efficient way to me for learning new things.
I wonder what more he offers with a full book.