This chapter introduces the foundational ideas that connect marketing and data science and prepares readers for data-driven analysis in marketing contexts. It begins by defining marketing and emphasizing its focus on understanding customers and creating value. The chapter then explains data science as the process of drawing insights and inference from data, and clarifies how the two disciplines work together: marketing frames the business questions, while data science provides evidence-based answers through data collection, modeling, and analysis. To support this connection, the chapter reviews essential statistical concepts, such as mean, variance, and the normal distribution, that are foundations for many data-driven analysis used throughout the book.