One word of caution though. Depends on which side of the Atlantic you are taking the test. There are quite a few differences in terminology (eg:Tail Rotor Drift vs Transalating Tendency; Ng,Nf vs N1 and N2 etc). That might be a little confusing to the beginner. But if you grasp the concept and have an instructor explain the similarities--- piece of cake.
I would recommend Shawn Coyle's book too. I use it as a refresher a lot and it is very easy reading.
I have tried Ray Prouty too
. NOT recommended for the beginners or the faint of heart and short attention span.
Alt3