Columbia Gnibersity College of Physicians and Surgeons 630 WEST 168TH STREET NEW YORK 32, N. Y. INSTITUTE OF CANCER RESEARCH FRANCI OF THE ELAFAELD HOSPITAL TY PF NEW YOR i K August 20, 1953 CANCER RESE CH LABORATORIES OF THE FACYLXY OF MEDICINE ; f Dr. Joshua Lederberg Department of Microbiology University of Wisconsin Madison, Wisconsin Deer Josh: Congratulations on your recent opus in Science. Would you be so good as to send me several reprints of your article so that I can retain my own copy which I have been exhibiting far and wide. I had occasion to learn a good deal more about your field when I attended a virus symposium at Cold Spring Harbor earlier this summer. I am sorry that you were not there. Hyan and I frequently talk about you. You have all of our best wishes. Dincerely, Si.