Origins: Genesis, Evolution and Biodiversity of Microbial Life in the Universe is the sixth unit of the book series Cellular Origins, Life in Extreme Habitats and Astrobiology (COLE) edited by Joseph Seckbach. In this book forty eminent scientists review their studies in the fields of Life from the beginning to the "Fact of Life". The history of Origin of Life and Astrobiology is well covered by these authors. Reviews cover the standard and alternative scenarios of the genesis of Life, while the chapters of "The First Cells" leading to the biodiversity and extremophiles of microbial Life. Among these extremophiles are the microbes living in the Life's limits, such as in high temperature, psychrophilic, UV radiation, and halophilic environments. The origin and history of Martian water is discussed followed by the possible biogeochemistry inside Titan. This new field of Astrobiology has been presented, from comets as a source of materials and Life on earth to the space for last Frontiers.