One of the most popular "dog stars" of midcentury America, Lassie, an intelligent, brave collie, demonstrated loyalty, compassion, and love toward humans and fellow animals in films for Metro-Goldwyn-Mayer from 1943 to 1951, in a television series from 1954 to 1974, in an animated Saturday-morning program from 1973 to 1975, and in a 1978 feature film update. Lassie's heroics included finding and rescuing lost people, caring for the sick and injured, and warning individuals about impending natural and human catastrophes. Through the Lassie stories, viewers gained an appreciation of the strong bond that can be forged between humans and canines and provided a role model for human interpersonal relationships.

The character of Lassie originated in a short story called "Lassie Come Home" by Eric Knight that appeared in a 1938 issue of the Saturday Evening Post. Knight had used his own devoted dog Toots as the model for Lassie, and the collie's story touched the emotions...