Geobiology studies Earth as a system and explores the past, present and future of the interaction of life with its environment. This GRC is designed to attract biofilm and microbial mat researchers, microbiologists, early life paleontologists, stromatolite sedimentologists, geochemists, and astrobiologists with the aim to explore the living Earth and its ancestry. We hope that this fruitful engagement will inspire the next generation of geo- and astrobiologists. Biofilms and sediment-stabilizing microbial mats pioneered microbe-mineral interactions that led to sedimentary structures such as microbially induced sedimentary structures (MISS) and stromatolites. Evidence for their activities may be found in banded iron formations, cherts, sandstones, and carbonate rocks. Isotope geochemistry and the study of biomolecules reveal the origins and evolution of metabolic pathways of early life. Biomineralization began as microbe mineral interactions that were later exploited by eukaryotes to form structural body parts allowing for further colonization of the planet. Understanding how these geobiological processes have left their mark on our planet Earth provides the clues for Astrobiologists to explore life on other planets.