W. D. Keller

Walter D. Keller was an American geologist and author whose work focused on clay mineralogy and sedimentology. Born in Clay County, Missouri, on March 13, 1900, he studied at the University of Missouri, the Missouri School of Mines and Metallurgy, and Harvard, then went on to teach geology at the University of Missouri for 43 years before retiring in 1970.

He was widely respected as both a teacher and researcher. An obituary in Clay Minerals describes him as an internationally known clay mineralogist and sedimentologist, and credits him with producing more than 300 articles and books. His research ranged from Missouri fire clays to uranium-bearing formations in the Colorado Plateau, and he also took part in the study of moon rocks collected during the first lunar landing.

Keller also wrote accessible geology books, including The Common Rocks and Minerals of Missouri and The Principles of Chemical Weathering. Those titles reflect what made his writing valuable: he could connect technical science with the real materials people see in the ground, in rocks, and in landscapes around them. He died in Columbia, Missouri, on March 23, 2001, at the age of 101.