Neurogenetic analysis of memory seeks to identify genes involved in behavioral plasticity, to characterize the cells and neuroanatomies in which they are expressed, and to define the biochemistries and cell biologies in which they participate. From the study of Drosophila (fruit flies) beginning in the 1970s, two fundamental notions became apparent. First, a complex circuitry, consisting of sensory inputs, central processing, and motor outputs from thousands of neurons, likely is required. In addition, hundreds to thousands of genes likely participate in the neuronal-synaptic plasticity underlying behavioral plasticity. Hence, a vertical integration of function, from gene to behavior, will entail five primary levels of experimental analysis: molecular-genetic, gene network computation, neurophysiological, neural network computation, and behavioral. Second, molecular biological work across the animal kingdom has revealed a remarkable degree of evolutionary conservation, from basic phenomenology of cell...