It is an honor to welcome Dr. Thomas H. Weller as the 40th Charles Franklin Craig lecturer. Dr. Weller is known to most of us. He is a past president of the society and has had an academic and professional career marked with recognition and honors. Dr. Weller graduated with honors from the University of Michigan in 1936 and then entered Harvard Medical School. During these years, which ended in 1940, he had a travelling fellowship from the Rockefeller Foundation for the purpose of studying malaria and public health. Following graduation he remained at Harvard as a teaching fellow in bacteriology until 1942 when he was ordered by the Army to report to the Puerto Rican Department Laboratory where he served as officer in charge of the parasitology, malaria, bacteriology and virus sections.Upon his return to Harvard and Children's Hospital in 1946, his academic and professional career steadily progressed, reaching a climax in 1954 when he was appointed the Richard Pearson Strong Professor of Tropical Public Health and Chairman of the Department at Harvard School of Public Health.