The alien encounter has long been a defining and popular subject of science fiction cinema. However, Stanley Kubrick's 2001: A Space Odyssey (1968) and Andrei Tarkovsky's Solaris (1972) are interrogative, complex, and distinct artistic accomplishments that stand apart from and above the conventional science fiction film. 2001 and Solaris not only represent but complicate the alien/human dichotomy; in the end, they destabilize the dichotomy and even suggest a radical synthesis of the dichotomous elements. 2001 and Solaris further emphasize epistemological and specifically anthropocentric limitations when it comes to understanding the alien or attempting to make sense of the alien encounter. Chapter 1 introduces the alien/human dichotomy in two representative science fiction films of the period, This Island Earth (1955) and Planet of Storms (1962). Chapter 1 provides some contextual and contrapuntal basis for the originality of 2001 and Solaris. Chapter 2 reviews critical literature directly and indirectly addressing alien and human identity, interpretations of symbolic forms such as the monolith in 2001 and "guests" in Solaris, and both films' ambiguous, multivalent endings. Chapter 3 (on 2001) and Chapter 4 (on Solaris) examine the alien/human dichotomy in specific scenes where an alien, non-human presence appears to be present or where an alien encounter significantly occurs. The two chapters analyze techniques such as the significance of the establishing shot and other shots or cinematographic effects, settings, point of view, and non-diegetic music. By way of conclusion, Chapter 5 compares 2001 and Solaris and makes the argument for the differences between-and departures from-the two film masterpieces and conventional science fiction films. Chapter 5 ends with further considerations of the argument and a broadening of the context. This dissertation should be of interest not only to science fiction scholarship in general but to film studies in particular. It aims to provide a sophisticated reading of 2001: A Space Odyssey and Solaris supported by recent criticism in an effort to join in the ongoing scholarly discussion and critical legitimatization of science fiction cinema.