At the time of Professor Light's death, the first edition of Intertidal Invertebrates of the Central California Coast: S.F. Light's Laboratory and Field Text in Invertebrate Zoology was practically out of print, and only a small amount of the work of revision had been carried out by the author. Since that date the work of revision has proceeded, more slowly than we would have wished, along the lines indicated by present and anticipated needs for a faunal manual of this sort. Recognizing that this manual will rarely, if ever, again be used as the principal text in any course in invertebrate zoology, but rather as an adjunct to standard texts or to an instructor's own syllabus, we have generalized much of the introductory material in the various sections and have omitted specific instructions for laboratory procedure in studying particular groups of animals. The section, Field Studies, has been modified to retain the material of general interest, including examples of the problems upon which Dr. Light engaged his classes, but material and schedules pertaining wholly to Dr. Light's conduct of classes at the University of California have been deleted. Some of the keys to fresh-water and terrestrial forms, which are better covered in other works, have also been dropped, and the main emphasis given to the intertidal invertebrate fauna. In most instances, keys and discussions have been completely rewritten rather than simply emended. In an over-all sense, we have edited freely in the effort to achieve a satisfactory and balanced text, reinforced in our efforts by the knowledge of Dr. Light's dissatisfaction with the first edition. Despite these efforts, we may echo Dr. Light's characterization of the work in his preface to the first edition, and state that the second is still "incomplete . . . and continually in process of revision . . . " If we bring this revision to publication without achieving satisfaction in its completeness, we have, at least, adhered to the tradition of the first. This title is part of UC Press's Voices Revived program, which commemorates University of California Press’s mission to seek out and cultivate the brightest minds and give them voice, reach, and impact. Drawing on a backlist dating to 1893, Voices Revived makes high-quality, peer-reviewed scholarship accessible once again using print-on-demand technology. This title was originally published in 1954.