I second that 212 man, having done my exams years previous I still read his first one (The Art and Science of Flying Helicopters) cover to cover and very impressed with it.
Recommended it to a friend who was about to sit his then CAA exams and his words were: “the first book that clear up those more complex P of F bits and it was paramount in me passing my exam”.
Also it says a lot about a person if he doesn’t plug his own book but recommend another (see above). Don’t get me wrong Prouty’s books are an institution but IMHO Shawn’s book reads easier and that’s a bonus on a sometimes “dry” subject that P of F can be.