"I have no hesitancy in saying that it is by far the best presentation of this very important subject that I have ever seen. It answers many important questions for which I have seen no answer elsewhere."--=Prof. William R. Manning, Purdue University.= "I have heard the lecture and read the book and do not hesitate to recommend it. It is all that a young man needs to read to inform him of his duties and his perils in this matter. The ethical ideals are high and the advice sensible and wise."--=Dr. Charles R. Henderson, Department of Sociology, University of Chicago.= "Some day Sexual Hygiene will have a place in the curriculum of every college. It is a subject that every college man does consider in one way or another, but often ignorantly, or under unwise guidance. Dr. Hall's book is so simple and sane as well as scientific, that I wish it might be in the hands of every college man in the country."--=Dr. George A. Coe, Northwestern University.= "I consider it admirable in both conception and execution. So far as I know, it is unique in its presentation of these matters, especially on the hygienic side and shall be pleased to recommend it at every opportunity."--=Dr. William T. Belfield, Bush Medical College, University of Chicago.= "The book seems to me calculated to be very useful, and should be in the hands of a large number of college undergraduates."--=Dr. Isaac Sharpless, President Haverford College.= "I have read the book and had other priests read it and all concur in my opinion that it is destined to become a powerful auxiliary to our young men in their struggle for a purer life. The language is not vague, but to the point, and every young man will understand it."--=Rev. A.M. Kirsch, University of Notre Dame.= "I have the strongest praise for the book as a whole--the biological foundation, directness, freedom from cant and prudery and the practical way in which the author gets to the level of his readers."--=Dr. C. Judson Herrick, Denison University, Ohio.= "I have read Dr. Hall's book with the keenest curiosity and interest. Why could not such a book have been in the hands of the youth of the past generations? We should have been all the better for it. The work seems to me to be simply and plainly stated. With such apparent thoroughness and good sense, good taste, I am sure the book will commend itself to every thoughtful reader."-=-Dr. Chas. M. Stuart, Garrett Biblical Institute, Evanston, Illinois.= [Illustration: (signed) Yours sincerely Winfield S. Hall] * * * * * THE BIOLOGY, PHYSIOLOGY AND SOCIOLOGY OF REPRODUCTION Also Sexual Hygiene with Special Reference to the Male. by WINFIELD S. HALL, Ph.D. (Leipzig), M.D., (Leipzig),