Sven Bernecker presents an analysis of the concept of propositional (or factual) memory, and examines a number of metaphysical and epistemological issues crucial to the understanding of memory. Bernecker argues that memory, unlike knowledge, implies neither belief nor justification. There are instances where memory, though hitting the mark of truth, succeeds in an epistemically defective way. This book shows that, contrary to received wisdom in epistemology, memory not only preserves epistemic features generated by other epistemic sources but also functions as a source of justification and knowledge. According to the causal theory of memory argued for in this book, the dependence of memory states on past representations supports counterfactuals of the form: if the subject hadn't represented a given proposition in the past he wouldn't represent it in the present. The book argues for a version of content externalism whereupon the individuation of memory contents depends on relations the subject bears to his past physical or social environment. Moreover, Bernecker shows that memory doesn't require identity, but only similarity, of past and present attitudes and contents. The notion of content similarity is explicated in terms of the entailment relation.