Antoine Lavoisier 
Elements of Chemistry: In a New Systematic Order, Containing all the Modern Discoveries [PDF ebook] 

Lavoisier is one of the giants of chemistry. In this book, he lays out all of the theories of early chemistry and how to conduct experiments. He ties the old chemistry (alchemy) into the new, and it is here that the kernels of modern chemical nomenclature begin. He is rightfully called "The Father of Modern Chemistry". Anyone who is serious about learning chemistry should read this book.