Viviparity combined with sustained invasive placentation is a unique reproductive innovation of placental mammals (Eutheria). This fact is remarkable as viviparity, of various kinds, is a quite frequent reproductive feature of animals in general. In this book, the authors argue that sustained invasive placentation faced a number of cell biological obstacles, known as biological paradoxa. In the evolution of eutherian mammals, each paradoxon was overcome by a specific evolutionary innovation that overcame the cellular biological constraint on the evolution of mammal-like viviparity. Each of these innovations also identifies specific mechanisms that entail clinical vulnerabilities of human pregnancy. The evolution of mammalian pregnancy is thus a paradigm of a significant evolutionary novelty, and this book exemplifies the conceptual tools necessary to explain evolutionary novelties in general, as well as the importance of an evolutionary and cell biological perspective on human reproductive health.

Günter Wagner is the Alison Richard Professor Emeritus of Ecology and Evolutionary Biology. After undergraduate education in chemical engineering, Wagner studied zoology and mathematical logic at the University of Vienna, Austria. He finished his PhD in theoretical population genetics in 1979 and conducted postdoctoral research at Max Planck Institutes in Göttingen and Tübingen, as well as at the University of Göttingen. Wagner began his academic career as assistant professor in the Theoretical Biology Department of the University of Vienna. He then moved to Yale University as a full professor of biology and has served as the first chair of Yale's Department of Ecology and Evolution. The focus of Wagner's work is on the evolution of complex characters. His research utilizes both the theoretical tools of population genetics as well as experimental approaches in evolutionary developmental biology. He has contributed substantially to the current understanding of evolvability of complex organisms, the origin of novel characters, and modularity. Günter Wagner is recipient of numerous awards, among them the prestigious MacArthur Prize, the Bobby Murcer Prize, and the Humboldt Prize. He received nominations as Gomperz Lecturer, University of California, Berkeley; Koopmans Distinguished Lecturer, IIASA Vienna; Sewall Wright Speaker, University of Chicago, IL. He is also a corresponding Member of Austrian Academy of Sciences, a Fellow of the American Association for the Advancement of Science, and a Fellow of the American Academy of Arts and Sciences. Wagner was elected to the National Academy of Sciences in 2018.

Mihaela Pavlicev, Univ.-Prof. Mag. Dr., Deputy Head of the Department of Evolutionary Biology, Head of the Unit for Theoretical Biology at the University of Vienna. Her research focuses upon the organismal features that enable evolvability of complex organisms. She seeeks to understand phenotypic evolution, patterns of heritable phenotypic variation in the developmental/physiological systems, and the consequences of specific patterns of variation over short terms under selection and drift.