NASA's Mars 2020 mission successfully landed the Perseverance rover in Jezero crater on February 18, 2021.This book provides the definitive pre-landing documentation of the Mars 2020 mission, its scientific payload elements, and its exploration area. The chapters in this volume include detailed descriptions of: The Perseverance mission, and its relationship to a possible Mars Sample Return campaign; The geology of the mission's exploration environment in Jezero crater; and The purpose, design and operation of all seven instruments aboard the rover...