Forgetting is importantly related to remembering, evidence possession, epistemic virtue, personal identity, and a host of highly-researched memory conditions. In this paper I examine the nature of forgetting. I canvass the viable options for forgetting’s ontological category, type of content, characteristic relation to content, and scale. I distinguish several theories of forgetting in the philosophy and psychology of memory literatures, theories that diverge on these options. The best theories from the literature, I claim, fail two critical tests that I develop (...) (the metacognition and prospection tests), underwriting arguments against the theories. I introduce a new theory about the state of forgetting—the learning, access failure, dispositional (LEAD) theory: to forget is to fail to access something that is both learned and either inaccessible or intended to be accessed. I argue that the LEAD theory of forgetting is the lead theory of forgetting. It passes the metacognition and prospection tests, and has several further virtues at no cost. Finally, I advocate reductionism about the process of forgetting; the process reduces wholly to states of forgetting. In particular, a process of forgetting is just a sequence of increasingly strong states of forgetting. (shrink)