This book has two principal objectives. The first is to provide an overview of existing knowledge about competition. The second is to organize this knowledge in such a way that new research paths are suggested. Such a treatment of competition is badly needed. Although there is a voluminous literature on the topic there is no recent synthesis to which experienced researchers or new students may turn. This is my attempt to provide such an overview. I have tried not only to summarize what is known, but also to stress the unknowns in the hope that some new and innovative research will result. A book such as this faces two challenges at the outset: the sheer volume of the literature, and the presence of established research traditions which determine how that literature is to be interpreted and understood. The literature on competition is as vast and diverse as beetles in the biosphere. How better to begin, then, than with the preface from Crowson's (1981) volume on the Coleoptera? He observed: To deal with so vast a group as the Coleoptera . . . is doubtless an over ambitious aim for any single author; it is inevitable that my attempt to do so will not satisfy specialists in their own particular fields.