This book came about as a result of a review I had written earlier on fea tures of cellular changes occurring during anuran metamorphosis. Only a limited treatment of this subject was possible in such a circumscribed work and only specific examples of organic change were dealt with. Thus the sins of omission weighed heavily, for so much information could not be included to provide a more comprehensive and authenticated account of the elaborate, complex, and far-reaching changes that an aquatic larva undergoes to become a terrestrial froglet. A good deal of my working life has been spent...