The label "essay film" is encountered with ever-increasing frequency in both film reviews and scholarly writings on the cinema, owing to the recent proliferation of unorthodox, personal, reflexive "new" documentaries. In an article dedicated to the phenomenon that he defines as the "recent onslaught of essay films," Paul Arthur proposes: "Galvanized by the intersection of personal, subjective and social history, the essay has emerged as the leading nonfiction form for both intellectual and artistic innovation."1 Although widely used, the category is under-theorized, even more so than other forms of nonfiction. In spite of the necessary brevity of this contribution, by tracing the birth of the essay in both film theory and film history, and by examining and evaluating existing definitions, a theory of the essay film can be shaped, some order in its intricate field made, and some light shed on this erratic but fascinating and ever more relevant cinematic form. Most of the existing scholarly contributions acknowledge that the definition of essay film is problematic, and suggest it is a hybrid form that crosses boundaries and rests somewhere in between fiction and nonfiction cinema. According to Giannetti, for instance, "an essay is neither fiction nor fact, but a personal investigation involving both the passion and intellect of the author."2 Arthur's framing of such in-betweenness is particularly instructive: "one way to think about the essay film is as a meeting ground for documentary, avant-garde, and art film impulses."3 Nora Alter insists that the essay film is "not a genre, as it strives to be beyond formal, conceptual, and social constraint. Like 'heresy' in the Adornean literary essay, the essay film disrespects traditional boundaries, is transgressive both structurally and conceptually, it is self-reflective and self-reflexive."4 Transgression is a characteristic that the essay film shares with the literary essay, which is also often described as a protean form. The two foremost theorists of the essay are, as is well known, Theodor Adorno and Georg Lukacs; both describe it as indeterminate, open, and, ultimately, indefinable. According to Adorno, "the essay's innermost formal law is heresy"5; for Lukacs, the essay must manufacture the conditions of its own existence: "the essay has to create from within itself all the preconditions for the effectiveness and solidity of its vision."6 Other theorists and essayists make similar claims: for Jean Starobinski, the essay "does not obey any rules"7; for Aldous Huxley, it "is a literary device for saying almost everything about almost anything"8; for Snyder, it is a "nongenre."9 As these examples indicate, many existing definitions of both literary and filmic essays are simultaneously vague and sweeping. Indeed, elusiveness and inclusiveness seem to become the only characterizing features of the essayistic; as Renov observes: "the essay form, notable for its tendency towards complication (digression, fragmentation, repetition, and dispersion) rather than composition, has, in its four-hundred-years history, continued to resist the efforts of literary taxonomists, confounding the laws of genre and classification, challenging the very notion of text and textual economy."10 As Jose Moure argued, the fact that we resort to a literary term such as "essay" points to the difficulty that we experience when attempting to categorize certain, unclassifiable films.11 This observation flags the risk that we accept the current state of under-theorization of the form, and use the term indiscriminately, in order to classify films that escape other labeling, as the following remark appears to endorse: "The essayistic quality becomes the only possibility to designate the cinema that resists against commercial productions." 12 The temptation of assigning the label of essay film to all that is non-commercial or experimental or unclassifiable must, however, be resisted, or else the term will cease being epistemologically useful, and we will end up equating very diverse films, as sometimes happens in the critical literature- for instance, works such as Sans Soleil/Sunless (Chris Marker, FR, 1983) and Fahrenheit 9/11 (Michael Moore, US, 2004), which have very little in common aside the extensive voice-over and the fact that they both present problems of classification. …