This book is based on the interesting one-hundred-plus-year history of the Club and its members. Plummers Island and the historic cabin on the Island have served as a common meeting area where the Club members have conducted research and held many social activities for over a century. The history has been written and revised over the years by members, and the biographical sketches also have been collected and written by the members. The Club was formed in 1900 and incorporated as a society in 1901 for scientists in the Washington, D.C., area. In recent years the Club has sponsored research by many non-member local scientists with grants totaling over $305,000. The cumulative total of 267 members represents all branches of natural science, with a strong emphasis on biology as the Club name indicates. In addition to the biologists there have been famous naturalists (e.g., John Burroughs), high-level administrators (e.g., Ira Gabrielson), and well-known artists (e.g., Roger Tory Peterson). Most members have been biological scientists, working for agencies in the Washington, D.C., area, who have published many articles and books dealing with biology and related subjects. The book is publIshed mainly for the benefit of the living Club members and for relatives of the deceased members. The members hope that the book will find its way into libraries across the country and that in the future, persons interested in some of the pioneer scientists, in the various professional areas of science, can obtain biographical information from a well-documented source. Most of the 542 illustrations of the members, cabin, and the Island have not been published previously. It is hopeful that the biographical sketches, pictures, and other information presented in this book can generate new information for future publications and for the website of the Washington Biologists' Field Club, which is updated frequently.