This dissertation is the first systematic study of Michelangelo Antonioni’s literary adaptations. From this vantage point, it re-envisions Antonioni’s cinema in terms of adaptive authorship, stylistic plurality, and medial impurity. While the analysis of Antonioni’s adaptations makes his cinema appear in an entirely new light in respect to traditional readings, his work as an adapter at the same time highlights the insufficiently explored potential – within the theory of adaptation – of adaptive practices as agents of a vivifying authorial, cultural, and medial hybridization. In the introduction I define Antonioni’s adaptations in terms of rites, and I illustrate their function within his filmography. Each of the five chapters in which my dissertation is organized focuses on one of Antonioni’s films, which it relates to his work as an adapter. In each chapter, the close analysis of the film is functional to the recognition of the elements that are incorporated in Antonioni’s cinema through his practices of adaptation. I complement my analysis by illustrating the specificity of each instance of adaptation, while also reconnecting them to the broader function that adaptation practices have for Antonioni’s cinema. My dissertation illuminates the stylistic plurality of Antonioni’s cinema and highlighting the crucial role played by adaptation in the inception and development of the three distinct consecutive stylistic phase that characterize his cinema. Challenging the assumptions underpinning the theories of authorship and medium specificity prevalent in the studies on Antonioni, my dissertation spotlights the impure intermedial constitution of his cinema and suggests rethinking his authorial identity in terms of adaptive authorship. In doing so, my dissertation theorizes adaptation as a ritual enactment of authorial, medial, and stylistic hybridization. By looking at Antonioni the adapter as both the agent of textual transformation and, in turn, the object of a different transformation, my study contributes to complicate in productive ways the understanding of the agency of the adapter within the theory of adaptation.