Microburst,
As you probably guessed I am (was) an engineer, so perhaps not the best person to judge whether Shevell's book is apt for non-engineers. Dick (I met him once) was Chief Aerodynamicist at Douglas and then went to Stanford, so his book is full of realistic data. Looking through it it seems to be about 95% good, understandable text and explanations, but some maths is inevitable - only you can judge if it is too much, but I think you could just take the maths for granted and read the text.
Anyway, it is : Fundamentals of Flight, by Richard S Shevell, published by Prentice Hall, ISBN 0-13-339060-8. I don't know whether it is still in print though, and I doubt you will get a .pdf version - it is over 400 pages.