Le Roy Crummer was born on April 15, 1872, in Elizabeth, Illinois. He received his undergraduate degree from the University of Michigan in 1893, and his M. D. from Northwestern University School of Medicine in 1896. Soon after graduation, Dr. Crummer became associated with his father, Dr. Benjamin F. Crummer, in practice in Omaha, Nebraska. At this time he also became an instructor in the University of Nebraska; he was named professor of medicine at that institution in 1919. His primary professional interest lay in the study of heart disease. He did notable Army service during World War I, particularly in giving instruction in cardiology. His general teachings in this subject were expanded into the important volume Clinical Features of Heart Disease, published in 1925. A lifelong bibliophile, in 1920 Dr. Crummer and his wife (an authority on Elizabethan literature) began assiduously to collect medical incunabula and manuscripts. Over the next decade, they made frequent trips through Europe and acquired an impressive collection of nearly five hundred items, most of which were deposited in the library of the University of Michigan. During this period, Dr. Crummer also published work in medical bibliography. In 1929 Dr. Crummer was named clinical professor of medical history and bibliography at the University of California medical school, a position which he held until his death in 1934.