This Precalculus text surveys traditional and additional content for a course in sequence after Algebra II and before Calculus or Statistics. While it goes before Calculus and Statistics, Precalculus is not an easier course. In fact, since it covers such a wide range of topics, requires deep problem solving and includes many new types of notation, many students find it challenging but essential for college level mathematics. The content in this text covers most state standards for Analysis, Trigonometry and Linear Algebra as well as the Common Core Standards suggested for a "Fourth Course" in high school. It was written by Mark Spong, an experienced Precalculus Teacher, and edited by his wife Kaitlyn Spong. Mark graduated from Harvard in 2007 with a BA in Mathematics and Stanford in 2008 with an MA in Education.