This book presents an overview of current views on the origin of life and its earliest evolution. Each chapter describes key processes, environments and transition on the long road from geochemistry and astrochemistry to biochemistry and finally to the ancestors of today´s organisms. This book combines the bottom-up and the top-down approaches to life including the origin of key chemical and structural features of living cells and the nature of abiotic factors that shaped these features in primordial environments. The book provides an overview of the topic as well as its state of the art for graduate students and newcomers to the field. It also serves as a reference for researchers in origins of life on Earth and beyond.