Roger Tory Peterson's A Field Guide to the Birds has inspired and educated generations of birdwatchers since it was first published in 1934. The quick-recognition system that he introduced in this guide is considered the greatest contribution to birding since the binoculars, and the Peterson Field Guide Series now comprises 50 volumes. With sales approaching 20 million copies, Roger Tory Peterson's legacy has been a major factor in the genesis of the modern environmental movement.
