No one needs reminding that we are well into a revolutionary phase in the study of evolution, systematics, and the interrelationships of organisms. To belabor the metaphor a little, to the thesis of Darwinian evolution and Mayrian systematics has been added a new cladistic antithesis which says that the search for ancestors is a fool's errand, that all we can do is determine sister group relationships of monophyletic taxa based on the analysis of derived characters. Consequently, our attention should be focused upon patterns which can be delineated, discussed, and modified in the light of new data, rather than upon processes which may only be the subject of untestable hypotheses. It is a change in approach that is not easy to accept for, in a sense, it runs counter to what we have all been taught, and it is particularly difficult for the paleontologist to accept because a major feature of the approach is a concentration upon living rather than on fossil forms. In fact, fossils are, in general, either difficult to use or irrelevant, or both, in terms of new attempts to set out the relationships of the major groups of organisms. The subject of this brief notice is a critically important new addition to the literature on this growing, dare I say evolving, subject.