This book is awesome. These six essays are selections from Feynman's Caltech lectures during the sixties, which have become famous for their accessibility to the general reader. I love that books like this exist. Feynman writes about the basics of classical and quantum physics with an emphasis on the conceptual, rather than mathematical, core of the science. Very little math or formulas, but plenty of diagrams to illustrate his points throughout the lectures. Great stuff.