Changes to myriad synapses throughout the brain must be coordinated every time a memory is established, and these synapses must be appropriately reactivated every time the memory is retrieved. Once stored, memories can be recognized (as a re-experienced input) or recalled (via different input, such as a name evoking the memory of a face or a scene evoking memories of an experience) by many routes. We remember what tables are as well as we remember a specific table, and we recognize objects despite seeing them from quite different angles, under different lighting, in different settings. Computational simulations of synaptic modifications (e.g., long-term potentiation) in distinct brain-circuit architectures illustrate how these minute changes can give rise to coherent properties of memory; how analyses of different brain areas yield derivations of disparate memory functions; and how interactions among connected regions give rise to still new...