This bulletin was written with three objectives in mind. First, it is designed to provide authorized names for the more common edible marine bivalve mollusks of California in the hope that these names will be used not only by the sportsmen but by the fishing industry. Secondly, it is an attempt to assess the economic importance to the State of these bivalves by putting on record the extent and location of the available bivalve-producing grounds, the number and abundance of the edible species, and, by contributing to a knowledge of their life histories, lay the foundation for such protective legislation as may in the future be found necessary. Thirdly, it proposes to make available to the amateur clam digger and amateur naturalist a means of identifying the more common and important bivalves. It is meant as a guide for any person interested in bivalve mollusks regardless of his technical knowledge and background, so scientific terminology is avoided wherever possible.