Driven by Discoveries, and enabled by leaps in technology and imagination, our understanding of the universe has changed dramatically over the course of the last few decades. Based on a broad and comprehensive survey of scientific opportunities, infrastructure, and organization in a national and international context, New Worlds, New Horizons in Astronomy and Astrophysics recommends an integrated program for ground- and space-based astronomy and astrophysics for the decade of the 2010s and beyond. The discoveries ahead will facilitate the search for habitable planets, shed light on dark energy and dark matter, and aid our understanding of the history of the universe and how the earliest stars and galaxies formed.