This document provides an overview of the concept of modern marketing. It begins by defining marketing and discussing its development over time. Specifically, it describes three eras: the production era, the sales era, and the era of the marketing concept. The production era focused on producing as much as possible, while the sales era emphasized convincing customers to buy existing products. The modern marketing concept orients the entire firm around customer needs and wants. The document then discusses the three basic propositions of the marketing concept and its focus on customers.