Focusing on two central questions — “What are we?” and “How Do We Know?” — HORIZONS: EXPLORING THE UNIVERSE, 14th Edition, helps you understand our place in the universe and how scientists work. Chapter-opening “Guideposts” and a conversational writing style make the content accessible and help you acquire an understanding of the universe (rather than just memorize basic facts); and online resources let you study where and when you want, to best meet your individual learning style.