The Evolution of Physics by Albert Einstein and Leopold Infeld. Interestingly (or unfortunately, or appallingly), as a physicist, I have never read anything written by Albert Einstein.
This book contains no math - quite a feat for a book about Physics. It is hard for me tell (because I already understand the content) how easily this book would be understood by the layman.
My sister used this text in college and for some reason, I have her copy. Never having read it, I decided I should.
I am enjoying it much more than I thought possible. As a Physics Adjunct, I think it may benefit my students on having read this, giving me better insight on how to explain things in different ways.
Oremus pro invicem!