Dr. Gerald A. Diettert practiced internal medicine and cardiology in Missoula, Montana, before enrolling at the University of Montana where he studied under Dr. H. Duane Hampton and received a Masters degree in History. Hampton was a professor of Western history whose research areas included the history of conservation and the development of national parks. Hampton had conducted his own research about George Bird Grinnell using sources from a variety of archival collections around the country and shared these files with Diettert. Diettert conducted additional research and presented his thesis, "Grinnell's Glacier," in 1990. The thesis was published by Mountain Press in 1992 with the title .

An author, naturalist and explorer who was one of the nation's foremost advocates of game and forest conservation, George Bird Grinnell was born in Brooklyn, New York on September 20. 1849, the son of George Blake and Helen Lansing Grinnell. When he was seven his family moved to Audubon Park, a section of Washington Heights in which noted ornithologist James Audubon had his estate. Years later, Grinnell would be the organizer of the first Audubon Society.

Upon receiving his undergraduate degree from Yale University in 1870, Grinnell went west for six months with an expedition of the Peabody Museum at New Haven to collect vertebrate fossils. In 1874 General Custer invited him along as a naturalist on his expedition to the Black Hills.

Grinnell received a Ph.D. from Yale in 1880. His work, however, was concentrated mainly in the West where he became well versed on the Plains Indians, writing about the Blackfeet, the Cheyenne and the Pawnees. He wrote authoritative volumes also about game birds of America, particularly ducks, emphasizing the sharp decline in numbers and species. In his lifetime he wrote twenty-six books and edited eight more. From 1880 to 1911 he served as editor and president of , a weekly periodical devoted to outdoor life. Grinnell co-founded the American Game Association in 1911 and was, at one time, chairman of the Council on National Parks, Forests and Wildlife. He was also affiliated with the National Parks association.

In addition, Grinnell was instrumental in the creation of Glacier National Park in Northwestern Montana, a reserve of one million acres of mountain country. The Grinnell Glacier in the St. Mary's Region in Montana, one of his discoveries, was named in his honor. Throughout his lifetime he wrote extensively in defense of preservation and conservation. An extensive traveler and explorer until well into his seventies, Grinnell suffered a heart attack at his home in New York in July of 1929. Although the initial prognosis was grim he recovered slowly. Age and persistent illness kept Grinnell in the East during his final years. He passed away on April 11, 1938 at the age of eighty-eight.