The Biology of Pelagic Tunicates is, to my knowledge, the only book dealing with the biology and ecology of these amazing organisms. This fact per se would make the book extremely valuable and attractive for any person interested in plankton ecology. Yet, its clarity, the amplitude of the subjects dealt, and the profundity of the knowledge presented convert the work in a milestone of plankton ecology. Most of this success is probably due to the fact that the authors are of greatest excellence and are known within the best experts in the field. The Biology of Pelagic Tunicates presents, thus, a clear summary of the present knowledge on these important, although quite unknown, marine organisms, dealing, among other subjects, with their anatomy, taxonomy, physiology and ecological relevance. We have not to forget, however, that this is a highly specialized book that is addressed to biologists or other scientists interested in the subject, but not to the common reader.