As a result, Homans joined a discussion group at Harvard called the Pareto Circle, which was led by Henderson and inspired by the work of Vilfredo Pareto. Henderson often discussed Vilfredo Pareto in his lectures. Pareto was a sociologist concerned with economic distribution. Pareto's theories and Henderson's lectures influenced Homans' first book, "An Introduction to Pareto", co-authored with fellow Circle member Charles P. Curtis. From 1934 to 1939 Homans was a Junior Fellow of the newly formed Society of Fellows at Harvard, undertaking a variety of studies in various areas, including sociology, psychology, and history. For his Junior Fellowship project Homans undertook an anthropological study of rural England, later published as "English Villagers of the Thirteenth Century" (1941) (see Homans 1984: 167). Homans was taken into the graduate program at Harvard; Pitirim Sorokin, founder of Harvard's sociology department in 1930, was credited with bringing Homans and Robert Merton into the program. From this knowledge gained, "the key idea that Homans took away from these studies was the centrality of interaction and the way sentiments developed between individuals as a consequence on interaction."