Papers in this Special Feature were presented at a symposium on the social biology of rodents that was held in June 2001 at the 81st Annual Meeting of the American Society of Mammalogists. Our decision to host a symposium on this topic resulted from our realization that although rodents have played a vital role in research on social behavior, no recent summaries of the social biology of these animals were available. Given the number of biological disciplines, research strategies, and species that are relevant to this topic, a comprehensive review of rodent social biology was not possible. Instead, in structuring the symposium, we chose to focus on a subset of behavioral issues for which studies of rodents currently are providing exciting new insights. Topics selected for inclusion—communication, kin recognition, philopatry, and sociality—are timely and are of considerable interest to biologists studying a wide array of animal taxa. Thus, papers presented in the symposium reflect recent advances not only in our knowledge of rodent social biology but also in our conceptual understanding of animal social behavior.