John Tyler Bonner and Robert M. May are Professors of Biology at Princeton University.

• *Frontmatter, pg. i*Contents VOL I, pg. v*Introduction, pg. vii*Notes and References, pg. xxxvi*Contents, pg. xlv*Introduction, pg. 1*Chapter I. The Evidence of the Descent of Man From Some Lower Form, pg. 9*Chapter II. Comparison of the Mental Powers of Man and the Lower Animals, pg. 34*Chapter III. Comparison of the Mental Powers of Man and the Lower Animals-Continued, pg. 70*Chapter IV. On the Manner of Development of Man From Some Lower Form, pg. 107*Chapter V. On the Development of the Intellectual and Moral Faculties During Primeval and Civilised Times, pg. 158*Chapter VI. On the Affinities and Genealogy of Man, pg. 185*Chapter VII. On the Races of Man, pg. 214*Chapter VIII. Principles of Sexual Selection, pg. 253*Chapter IX. Secondary Sexual Characters in the Lower Classes of the Animal Kingdom., pg. 321*Chapter X. Secondary Sexual Characters of Insects, pg. 341*Chapter XI. Insects, Continued.-Order Lepidoptera, pg. 386*Front Matter 2, pg. I*Errata, pg. II*Contents VOL. II., pg. III*Postscript, pg. VII*Chapter XII. Secondary Sexual Characters of Fishes, Amphibians, and Reptiles, pg. 1*Chapter XIII. Secondary Sexual Characters of Birds, pg. 38*Chapter XIV. Birds-Continued, pg. 99*Chapter XV. Birds-Continued, pg. 154*Chapter XVI. Birds-Concluded, pg. 183*Chapter XVII. Secondary Sexual Characters Of Mammals, pg. 239*Chapter XVIII. Secondary. Sexual Characters of Mammals- Continued, pg. 274*Chapter XIX. Secondary Sexual Characters of Man, pg. 316*Chapter XX. Secondary Sexual Characters of Man-Continued, pg. 355*Chapter XXI. General Summary and Conclusion, pg. 385*Index, pg. 406*Table of the Principal Additions and Corrections to the Editions of 1874, pg. 477

"[This work] is second only in importance to the Origin of Species ... among Darwin's works and the book in which he uses the word evolution for the first time."--Natural History