We live in a time of extraordinary discovery and progress in astronomy and astrophysics. The next decade will transform our understanding of the universe and humanity's place in it. Every decade the U.S. agencies that provide primary federal funding for astronomy and astrophysics request a survey to assess the status of, and opportunities for the Nation's efforts to forward our understanding of the cosmos. Pathways to Discovery in Astronomy and Astrophysics for the 2020s identifies the most compelling science goals and presents an ambitious program of ground- and space-based activities for future investment in the next decade and beyond. The decadal survey identifies three important science themes for the next decade aimed at investigating Earth-like extrasolar planets, the most energetic processes in the universe, and the evolution of galaxies. The Astro2020 report also recommends critical near-term actions to support the foundations of the profession as well as the technologies and tools needed to carry out the science. Table of ContentsFront MatterSummary1 Pathways to Discovery: From Foundations to Frontiers2 A New Cosmic Perspective3 The Profession and Its Societal Impacts: Gateways to Science, Pathways to Diversity, Equity, and Sustainability4 Optimizing the Science: Foundations5 Evaluating and Balancing the Operational Portfolio6 Technology Foundations and Small- and Medium-Scale Sustaining Programs7 Realizing the Opportunities: Medium- and Large-Scale ProgramsAppendixesAppendix A: Statement of Task, Additional Guidance, and Panel DescriptionsAppendix B: Report of the Panel on Compact Objects and Energetic PhenomenaAppendix C: Report of the Panel on CosmologyAppendix D: Report of the Panel on GalaxiesAppendix E: Report of the Panel on Exoplanets, Astrobiology, and the Solar SystemAppendix F: Report of the Panel on the Interstellar Medium and Star and Planet FormationAppendix G: Report of the Panel on Stars, the Sun, and Stellar PopulationsAppendix H: Report of the Panel on an Enabling Foundation for ResearchAppendix I: Report of the Panel on Electromagnetic Observations from Space 1Appendix J: Report of the Panel on Electromagnetic Observations from Space 2Appendix K: Report of the Panel on Optical and Infrared Observations from the GroundAppendix L: Report of the Panel on Particle Astrophysics and GravitationAppendix M: Report of the Panel on Radio, Millimeter, and Submillimeter Observations from the GroundAppendix N: Report of the Panel on State of the Profession and Societal ImpactsAppendix O: Independent Technical, Risk, and Cost EvaluationAppendix P: Acronyms and AbbreviationsAppendix Q: Committee and Panel Biographical Information