From the "Roger Tory Peterson's field guides and the other books which bear his name have instructed millions of people in the richness of the natural world. If we were to single out his most important contribution, would it be these remarkable books? His brilliantly life-like portraits of birds? His extraordinary effectiveness as a spokesman for conservation and the environment? His greatest contribution, I believe, is the sum of these - our enlarged awareness."
Good general overview of Peterson but pulls its punches. You can tell, reading between the lines, Peterson was an exceptional birder but a terrible human being. I’d recommend finding a biography where the author(s) aren’t enthralled by the man.