Temperate, nutrient-rich waters along the west coast of North America support highly diverse assemblages of benthic flora and fauna. This chapter summarises recent literature on community composition, species interactions and interactions between species and the environment in rocky subtidal habitats of the north-east Pacific. Subtidal research in the region has long emphasised top-down processes, although these processes vary spatially and may be secondary to abiotic forces in some locations, particularly in the south. Recent research has highlighted the importance of mesoscale oceanographic processes, rapid anthropogenic changes and complex competitive and facilitative interactions in shaping north-east Pacific rocky bottom assemblages. Advances in genetics and chemistry are currently providing insights into paleogeographic history and the interplay of environmental variables and biotic interactions over time; these tools will be essential for anticipating ecosystem response to ongoing, rapid, anthropogenic-induced abiotic changes. Expanded long-term observational studies, as well as field experiments that clarify complex species interactions, are needed to support nearshore managers in the region respond to anthropogenic change.