Understanding planetary habitability is one of the major challenges of the current scientific era, and is a vast inter-disciplinary undertaking that combines planetary science, climate science, and stellar astrophysics. This book provides an overview of the many processes that influence the energy balance of planetary surface environments and control the sustainability of temperate conditions. These factors include such aspects as the influence of stars, the atmospheres and interiors or planets, and the orbital dynamics of planetary systems. Also described are the concepts behind the habitable zone, lessons learned from solar system data, and the vast opportunities that are provided by exoplanet discoveries, both now and into the future. Key Features: Summarises current exoplanet discoveries relevant to habitability Aimed at graduate students and researchers with an interest in exoplanets and astrobiology Describes the primary factors that influence the habitability of a planet Emphasises the need for in situ data in our solar system Covers the degeneracy of geosignatures and biosignatures.