We use both field and laboratory studies to investigate the evolution of life-history traits in threespine stickleback (and to a lesser extent ninespine stickleback, Pungitius pungitius; and fourspine stickleback, Apeltes quadracus). Much of this research is based on annual (1992-present) sampling of 50-70 sites in the Cook Inlet region of Alaska, USA, and on less consistent sampling of populations in southern British Columbia, Canada (specimen collection). We have documented extensive within- and among- population variation in female reproductive traits including egg size, fecundity, size at first reproduction, as well as correlations among traits such as egg and clutch size (Baker, Heins, King). These data have guided experimental research including ongoing research on the function of egg size under varying intensities of foraging competition among fry (O’Brien). The multi-year data base has also enabled us to document rapid evolutionary change within populations. We are now initiating research on apparent population differences in the patterns of senescence across populations.