McClung spent many years working with the New York Zoological Society and then the National Geographic Society before turning his attentions to writing. The True Adventures of Grizzly Adams is one of more than fifty books that the author has produced on wildlife and the environment. He has a clear understanding of animals and a devotion to the protection and propagation of nature.
In the acknowledgments, McClung discusses his sources of information on Ad-ams, giving special credit to Theodore H. Hittell’s 1860 biography, The Adventures of James Capen Adams, Mountaineer and Grizzly Bear Hunter, of California, and Richard Dillon’s more recent The Legend of Grizzly Adams, California’s Greatest Mountain Man (1966). He also discusses his constant attempt to cull fact from fiction, to reduce exaggeration and legend to their actual historical dimensions, in rendering Adams’ “true” adventures. This was not always an easy task, as people such as Adams and Barnum were easily given to glorifying the truth, and McClung provides reminders of the speculative nature of many passages throughout the text.
When The True Adventures of Grizzly Adams appeared in 1985, it earned generally supportive reviews. While The Bulletin of the Center for Children’s Books criticized the writing as awkward and repetitive, it praised the author’s research and notes. Ethel R. Twichell in Horn Book and Ilene Cooper in Booklist both compared the biography favorably with the popular and highly fictionalized film and television series on Adams, noting McClung’s willingness to depict Adams’ brutality. The most positive critique appeared in the School Library Journal, where George Gleason admired the book’s ambiance, use of maps and illustrations, and general smoothness. He wrote that McClung’s account would bring history to life for any true adventure lover.