Each paper in this collection has been selected for one or more reasons. It may have served to focus attention on a particular facet of genetics. It may illustrate well the impact the study of genetics has on biology or on social and racial relationships. It may have embodied a particular idea unique at the time of publication that has led to extensive research by other geneticists, in many cases still continuing today. It may provide a brilliant example of the use of the scientific method. It may furnish a clear-cut, concise illustration of incisive reasoning. One or two have the added virtue of having been written in an entertaining style.
In each case, they are evidence of work considered to constitute "classic" contributions to the science of biology. Taken as a unit, they have done much to give form and direction to genetic research. Their vitality is unimpaired by age, and their repeated citation in bibliographies of current literature or on seminar reading lists testifies that they are still important sources of information.
You should not expect, and will not find, any attempt by an author to "write down" to the level of his readers, for the primary concern is neither popularization nor condensation, but rather, adequate presentation. There is an assumption by the authors that the reader has some biological background. Lack of this background should not handicap anyone in following the development of the basic ideas. Most of the major steps in the development of the gene theory are here, and the nature of the material discussed by each author was as new to biology at the time of writing as to any reader meeting it for the first time today.
This collection of papers served as the basis for a course in introductory biology taught for two years at Brown University. Many of these students had had no previous training in biology, but they demonstrated most satisfactorily that a neophyte in science can read, understand, and profit from a direct experience with the original literature of a particular field. Some guidance was necessary, and much was given in class. It is presented here in the form of an introduction to each paper. Little or no interpretation of the paper will be found in the introduction, however, for this interferes with the relationship between the author and the reader. All authors attempt to express their ideas clearly to the reader, and it is only fair to let them do so if they can. At the same time, the reader who follows an author's logic can feel that he has received his information from the primary source, and he is no longer dependent upon second hand interpretation of research.
It is my pleasure to acknowledge the permission granted by the publishers and authors to reproduce the papers in this volume. Citations to the original source are included with each paper. All of the journals are still being published except the Report of the Evolution Committee of the Royal Society, and they contain a continuing record of recent activities and researches. It would repay the reader to look over them occasionally to see what solutions have been offered to the many ques-