Geoffrey Moore's Crossing the Chasm is a classic business book that explains how to market disruptive technologies to mainstream customers. The book focuses on the "chasm," a gap that exists between early adopters of a new technology and the larger mainstream market. Moore argues that companies must have a clear strategy for crossing this chasm if they want to achieve mass market success. The book offers a framework for developing a market segmentation strategy, defining a compelling reason to buy for pragmatist customers, assembling a whole product, and positioning the product in a way that makes it easy to buy. Moore also discusses the importance of building partnerships and alliances to create a complete ecosystem around the product. Overall, Crossing the Chasm provides valuable insights for any company trying to bring a new technology to market.