Context reinstatement is the process by which we incorporate thoughts from our past into our current mental state. This chapter is concerned with characterizing the cognitive and neuropsychological underpinnings of context reinstatement. Modern theories of context reinstatement are inextricably tied to theories of how we process and perceive the present. The primary goal of this chapter is to present a conceptual framework for characterizing how experiences unfold in time, and how our mental states at each moment relate to our experiences. This framework allows us to compare, contrast, and test different theories of context reinstatement. A second component of this chapter is concerned with two fundamental properties of how our experiences unfold, and how we perceive and remember them: scale invariance and event segmentation. The chapter concludes with a reflection on the proposed role of context reinstatement in facilitating a range of important memory-related cognitive functions.