Driven by optimism, consumers often purchase products that they are unable to use at the time of purchase, in anticipation that they may be able to do so in the future. For instance, people often buy clothing that is presently too small for them. This dissertation examines the antecedents and consequences of such anticipatory purchase behavior, thereby illuminating both the substantive domain of anticipatory purchasing and providing theoretical insights into the nature of optimism. The first part of this dissertation investigates the fundamental question of why consumers engage in anticipatory purchase. Starting from the intuitive notion that optimistic individuals are more likely to engage in anticipatory purchase, I draw upon ideas from three different literatures, on optimism, mental simulation and goals, to build an overall framework that explains anticipatory purchasing. My conceptualization posits that the positive impact of optimism on anticipatory purchasing is moderated by a sequence of theoretically-derived factors; namely, style of processing (imagery vs. analytical), content of processing (process vs. outcome-focus) and depth of processing (unconstrained vs. constrained). A set of six experiments across different domains provides support for the predictions derived from this framework. The second part of this dissertation looks at the downstream consequences of anticipatory purchase. Here, I investigate how the anticipatory purchase decision affects consumers' likelihood to engage in subsequent behavior that is consistent with the purchase (e.g., buying exercise equipment after purchasing a pair of jeans that is currently one size too small). Once again integrating insights from goals research with those from the mental simulation literature, I show across five experiments that the specific mental simulation (outcome- vs. process-focus) that individuals use when making their anticipatory purchase decision, together with the decision to buy or not buy, can lead optimists and pessimists to variously infer either progress or commitment towards the goal. These inferences drive different post-purchase decisions, which may be goal-congruent or not. Taken together, these results provide fundamental insights into the mechanisms underlying consumer optimism and the dynamics of optimistic behavior.