This dissertation analyzes the syntax and processing of adjunct control. Ad- junct control is the referential relation between the implicit (PRO) subject of a non-finite adjunct clause and its understood antecedent, as in the temporal adjunct in ‘Holly1 went to bed [after PRO1 drinking milk]’, or the rationale clause in ‘August1 sat on the couch [in order PRO1 to read library books]’. Adjunct control is often as- sumed to involve a syntactic ‘Obligatory Control’ (OC) dependency, but I show that some adjuncts also permit what is referred to as ‘Non-Obligatory Control’ (NOC), as in the sentences ‘The food tasted better [after PRO drinking milk]’ and ‘The book was checked out from the library [in order PRO to read it]’, where PRO refers to some unnamed entity. I argue that for some adjuncts, OC and NOC are not in complementary distribution, contrary to assumptions of much prior literature, but in agreement with Landau (2017). Contrary to implicit assumptions of Landau, however, I also show that this OC/NOC duality does not extend to all adjuncts. I outline assumptions that Landau’s theory would have to make in order to accommodate the wider distribution of OC and NOC in adjuncts, but argue that this is better accomplished within the Movement Theory of Control (Hornstein, 1999) by relaxing the assumption that all adjuncts are phases. Even in adjuncts where both OC and NOC are possible, OC is often strongly preferred. I argue that this is in large part due to interpretive biases in processing. As a foundational step in examining what these processing biases are, the second part of this dissertation uses visual-world eyetracking to compare the timecourse of interpretation of subject-controlled PRO and overt pronouns in temporal adjuncts. The results suggest that PRO can be interpreted just as quickly as overt pronouns once the relevant bottom-up input is received. These experiments also provide evidence that structural predictions can facilitate reference resolution independent of next-mention predictions.