A seminal work on comparative psychology and the evolution of behavior, this book provides valuable insights into the minds of animals and the roots of human cognition. Featuring a posthumous essay by one of history's greatest naturalists, this volume is an indispensable resource for anyone interested in the history of science or the evolution of life on Earth.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it.This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.