Deep biosphere research is at the scientific frontier of bio- and geo-related sciences, yet it is largely underexplored. In terms of volume, deep subsurface settings represent some of the largest microbial habitats on the planet, and the combined biomass of the deep biosphere encompass the largest living reservoir of carbon, excluding land plants. However, before plants colonized land (ca. 400 Ma), the deep biosphere outweighed the surface biosphere by about one order of magnitude, providing a new “deeper” perspective on the history of life on Earth. Paradoxically, the paleo-record of the deep biosphere is still largely uncharted and neglected. The aim of this meeting is to highlight current research of deep life through time and bring together researchers from various disciplines. The scope of the meeting will bridge paleobiology, geochemistry, geobiology, microbiology, and astrobiology Deciphering the fossil record of the deep biosphere is a challenging task, but when successful, will unlock doors to life`s cryptic past.