With an introd. by Nathan M. Newmark. With an introd. by Julian S. Huxley. With an introd. by Martin Gardner. With an introd. by W. T. Stearn. with an introd. by Viola Meynell. With an introd. by Frank Wells. With an introd. by Pierre Chevenard. with an introd. by] Israel Gerver. With an introd. by George Sherburn. With an introd. by Lord Horder.