The cognitive neuroscience of memory aims to understand how we record, retain, and retrieve experience in terms of memory systems - specific neural networks that support specific mnemonic processes. Recent advances in functional neuroimaging have provided reliable tools to probe a set of brain operations specifically related to memory formation, consolidations and/or retrieval. Within these domains several basic operations like contextual and acontextual memory operations have been characterized in great detail. Studying the declarative memory system during major depression is fundamental, because declarative memory, even for emotionally neutral information, is affected early on in the course of the disease. This suggests that a causal role and a bias for negative memories is one of the most important cognitive maintenance factors of depression. Hence, we apply our fundamental research to probe the neural underpinnings of depression. So far, we established two lines of research on this topic. The first provides a mechanistic account for gonadal steroid hormone effects on mood regulation and memory. The second addresses functional disintegration of brain regions mediating memory in depression before structural disintegration takes place. These lines of research will be highlighted and results of ongoing studies will be shown in the following lectures.