Samuel Wood Geiser, biologist and historian of science, son of Matthäus and Maria Ann Lucas (Wood) Geiser, was born at Independence, Iowa, on June 11, 1890. He attended Upper Iowa University, where he received a bachelor's degree in 1914 and a master's degree in 1919, and Johns Hopkins University, where he was awarded a Ph.D. in 1922. Geiser taught for four decades: at Guilford College in North Carolina (1914–16), Upper Iowa University (1917–19), Washington University in St. Louis (1922–24), and Southern Methodist University (1924–57). He pursued interests in science, classical literature, languages, and history. Despite a heavy teaching load he compiled a lengthy personal bibliography. He is best known for his research on isopods, an order of Crustacea. He is also remembered for his research in Naturalists of the Frontier (1937), a study of the history of scientific exploration in the Southwest and the first book published by the SMU press. In 1945 Geiser was named editor of Field and Laboratory (Journal of the Graduate Research Center after 1960) at SMU. He served there until 1961. He was also a contributing editor of the Southwest Review and a contributor to the Dictionary of American Biography.
He was a fellow in the American Association of the Advancement of Science, an honorary life fellow in the Texas Academy of Science, president in 1927–28 of the North Texas Biology Society, and a member of the American Society of Zoologists, the American Microscopy Society, the History of Science Society (council member, 1946–48), the Texas State Historical Association, the Philosophical Society of Texas, and the American Association of University Professors. Among his honors were membership in Phi Beta Kappa and an honorary doctor of science degree awarded by Upper Iowa University (1934).
Geiser married Bessie Adella Teeple on December 28, 1916, and they had two children. Mrs. Geiser died in 1973, and Geiser died on August 28, 1983, at New Hartford, New York.