The value chain is a business management concept that was first described in 1985 by Michael Porter in his best-selling book, Competitive Advantage: Creating and Sustaining Superior Performance. The value chain refers to the progression of activities undertaken by a company in order to deliver a valuable good or service to its customers. It encompasses the sourcing of raw materials or the creation of a service to processing, manufacturing, and all other steps leading to the purchase of the product or service by a customer.