The Nature of Chemical Bond
This was a collection of ideas from Paulings previously published papers and made a huge impact on the way the chemical bond was viewed. Previously the approach had been an empirical one, but his use of quantum mechanics and diffraction techniques led to a much more theoretical one. Such was the popularity of the book it was translated into 13 different languages and revised three times. Below are a few of the most important ideas which are still very relevant today.
Image from http://osulibrary.oregonstate.edu/specialcollections/coll/pauling/bond/pictures/large-chemical-bond-editions.html