Selby took part in either three or four field expeditions to Antarctica, including in 1968-69, 1971-72, and 1978-79. On the first of these, he became the first geomorphologist to travel to Antarctica. The 1978-79 trip to the Britannia Range-Darwin Glacier region was led by Selby, and mapped exposures in the McCraw Glacier area, and discovered iron meteorites on Derrick Peak. Selby also made expeditions to the Sahara, Namib, and Atacama Deserts, as well as to the Himalayas and Colorado. He also visited the Eastern Mediterranean after developing a research interest in archaeology and human evolution and dispersion. In 1980, Selby was appointed as a professor of earth sciences at Waikato. During his academic career, he wrote six books and more than 80 refereed scientific papers.