Isoflavones are naturally occurring molecules present in significant amounts in many leguminous, some of which are edible plants. Isoflavones exhibit similarities in their chemical structure with steroidal estrogens, which allows them to trigger some of the endogenous physiocellular signalisation processes of estrogens that are known to occur naturally within living organisms. In fact, isoflavones mediate numerous health effects mainly related to their estrogenic and/or anti-estrogenic actions. Some of these effects are oestrogen receptor-mediated physiological phenomena such as those linked to the hypothalamo-hypophyso-gonadal axis. This book provides in vitro, animal, and clinical data intending to highlight the impact of isoflavones on the physio-cellular features of the hippocampal formation plasticity and, therefore, on the hippocampus-dependent cognitive brain function.