This book is all about solving authentic problems in real word contexts. The contexts have been chosen with two goals in mind: 1) To resonate with high school students' interests, and 2) to demonstrate the broad applicability of mathematics. Each context meets at least one of these goals, and some meet both goals. Embedded in each context is some sort of decision so that students are introduced to mathematics as a decision-making tool. The contexts are varied and include choosing the best wireless plan, optimizing production at a skateboard factory, minimizing the cost of reducing pollutants, scheduling workers in a pizzeria, choosing the right mix of colleges to apply to, and finding the best location for a disaster response facility. Throughout the book, students will be making sense of problems, persevering in their solution, mathematically modeling real-world contexts, using appropriate tools when necessary, and attending to the precision of results.