United States dentist. Robert Theodore Craig was born at Long Beach, California, and earned a BSc from University of California, Los Angeles before training in dentistry at the University of Southern California. He and his wife, Ina, who was his frequent companion on botanical trips, had a successful dental practice in Baldwin Park, California. Beginning in 1928, and with a variety of companions, he made numerous trips in the American Southwest and to various parts of Mexico mainly in search of "pincushion cacti" (Mammillaria). With G.E. Lindsay, he made a five-week trip into the rugged Tarahumare Mountains of Chihuahua on muleback in 1939. Craig collected virtually every known species of the group and in 1945 published The Mammillaria Handbook. After the monograph was published, Craig's interest gradually turned to orchids and his cactus collection was eventually dispersed. Craig served as president of the Cactus and Succulent Society of America in 1949 and 1950.

Sources:
V.F. Martin, 1986, "In Memoriam: Robert T. Craig, DDS, FCSS, 1902-1986", Cactus and Succulent Journal (U.S.), 58: 160.