This work is a review of new researches in the evolutionary morphology of hard and soft tissues, molecular phylogeny, and all aspects of currently active research, on the evolutionary history of the mammals. The first volume presents a comprehensive analysis of the evidence for the Mesozoic origin and differentiation of non-placental mammals, whilst the second covers the placentals. Emphasis is placed on understanding the evolution of morphological characteristics, on the fossil record, and on the construction of phylogenies based on the analysis of characters and on mammalian distribution. Of interest to paleaontologists, mammalogists, and taxonomists. A key reference.