This book uses mathematics to study problems arising in areas such as Genetics, Finance, Medicine, and Economics. The reader learns how to model a real situation, such as steroid-testing in athletes or environmental cleanup. They learn how to analyze that model in relationship to the real world, such as making recommendations for optimal steroid testing to avoid cheating or determining the minimum time required to adequately clean up a polluted lake. Often the results will be counterintuitive, such as finding that an increase in the rate of wildlife harvesting may actually decrease the long-term harvest, or that a lottery prize that is paid out over a number of years is worth far less than its advertised value. It is precisely this use of mathematics that illustrates and models real-world issues along with questions that bring the value of mathematics to life for students, enabling them to see, perhaps for the first time, the utility of mathematics.