Several decades ago, as a young scientist, I often received advice from a notmuch-older Edward O. Wilson, especially during many long days of field work on small mangrove islands in Florida Bay. Some of it was direct and explicit—what to do, what not to do. But most of the advice was indirect, delivered during riveting discussions about what scientific discoveries and developments really advanced a field and why some disciplines seemed to advance more rapidly than others, or about personal squabbles that may have even retarded science a bit, and certainly did not advance it. Now, as an old scientist, I am fascinated reading 20 letters that Wilson has penned specifically for young scientists. In many ways he has been remarkably consistent with what he told me nearly 50 years ago in Florida Bay. The letters, each a chapter primarily addressing a specific topic, draw heavily from Wilson’s own remarkable trajectory from a young boy in Alabama obsessed with snakes and black widow spiders to one of the world’s leading biologists with enormous contributions in ecology, evolution, myrmecology, behavior, conservation, and biogeography. Though the book is ostensibly for young people, not-so-young people will also enjoy it and find much inspiration. Some chapters are clearly aimed at people about Wilson’s age when he was exploring Alabama swamps in his quest to become an Eagle Scout. Others seem to target graduate students, post-doctoral fellows, and beginning faculty. Yet the book, with a style that transcends the ‘‘young adult’’ genre, will engage any scientist. In fact, because of the autobiographical material, the thoughtful insights, and a few bombshells Wilson detonates along with way, this book is difficult to put down. Those who have read his autobiography, Naturalist [1], will recognize some of the vignettes Wilson has chosen as vehicles for his advice. But even for stories that are well-known, he presents new interesting details and often enlightening context. Wilson as a child chasing butterflies in Washington, D.C. and Alabama. Wilson as a teenage herpetologist teaching Boy Scouts how to handle (or, as it were, how not to handle) venomous snakes. Wilson as a young ant enthusiast on the trail of the large primitive ant Daceton armigerum in Surinam—these or any of several other short narratives all give some insight into the underlying passion that he sees as the single most crucial attribute of a good scientist. Find the passion that grips you and follow it, no matter training or lack of it, and don’t worry if it seems out of vogue. A second piece of advice is perhaps more surprising—seek some area of science that is not in fashion. ‘‘If a subject already is receiving a great deal of attention...stay away from the subject.’’ He formalizes this as Principle Number Three: ‘‘March away from the sound of guns. Observe the fray from a distance, and while you are at it, consider making your own fray.’’ When Wilson discovered ants, not many myrmecologists occupied the scene. Today myrmecology might not be a great choice, according to Principle Number Three, but one presumes that sufficient passion and creativity can allow an exciting, rewarding career even in such a crowded field—as witness Corrie Saux Moreau, Wilson’s last myrmecological doctoral student. He uses Moreau (now Assistant Curator at the Field Museum and a leading expert on ant systematics) to exemplify another trait that he sees as necessary for a successful career—enough self-confidence in one’s own ideas to persevere in the face of obstacles and skepticism that others might put in your way. Less controversial might be Principle Number Five: ‘‘For every problem in a given discipline of science, there exists a species or other entity or phenomenon ideal for its solution.’’ For Wilson, the red imported fire ant (Solenopsis invicta) exemplifies this principle. His research on its behavior led Wilson to discoveries that helped shape the entire discipline of sociobiology and made the species a classic case study in chemical ecology. However, another part of Principle Number Five is more surprising: ‘‘For every species or other entity or phenomenon, there exist important problems for the solution of which it is ideally suited.’’ Wilson relates this aspect of the principle to the fact that, of several million species on earth, at most Wilson EO (2013) Letters to a Young Scientist. New York: Liveright (W.W. Norton). 245 p. ISBN 978-0871403773 (hardcover). US$21.95. doi:10.1371/journal.pbio.1001629.g001