This chapter’s protagonist, Richard M. Barsam (1938–), is the second among the thirty-eight definitors discussed thus far to be alive as I write about them. He is also the second historian of the 1970s, following Jacobs (Chap. 16 herein), to establish the American, British, and Continental Documentary narrative. For Jacobs, Barsam, and the third historian in this triumvirate, Erik Barnouw (Chap. 19 herein), Documentary is broadly perceived as, among other perspectives, a historical stratum of communicational activity. The chapter begins with an exploration of “Defining Nonfiction Film,” the title given to the opening chapter in his 1973 book Nonfiction Film: A Critical History. After he establishes the essential nature of the “problem of the definition,” he proceeds to address his central concept: nonfiction film. He posits that when the definiendum is evasive, fuzzy, and tends toward expansiveness—meaning that it is in constant temporal, aesthetic, and stylistic flux, and, consequently, a challenge to pin down—the theorist essentially has two basic options: (1) to denounce the definiendum’s definability or (2) to expand the measure of that definiendum’s roof-structure. In other words, Barsam’s logic unfolds in a scissors-like motion: on the one hand, decreasing the resolution of the inspection, while on the other, amplifying the measuring scale.