Micrographia

"The Reason of making Experiments is, for the Discovery of the Method of Nature, in its Progress and Operations."

Micrographia is a landmark in human literature; the first book to include illustrations of organisms (such as insects and plants) through microscopes; the first major book released by the Royal Society; the first popscience book (definitely the first bestseller in science). And, perhaps most surprisingly, the book that first used the term 'cell'.

"The most ingenious book that ever I read in my life."
Samuel Pepys