Whilst not mandatory, this book (this series of books) are frequently provided or highly recommended by flight schools in the U.K. as part of PPL courses. Even if you're not intending to learn to fly, but want to understand how and why a light aircraft behaves as it does, or even just know how to use a flight simulator more realistically, you won't go far wrong. I would recommend this along with Volume 4, 'The Aeroplane - Technical' as the minimum requirement for your library.
Note that they do assume a degree of intelligence on the part of the reader, however most people aiming to become a qualified pilot will have no problem whatsoever in understanding the material presented.