The author of the book, Fred Reichheld, suggests that companies ask their customers one question that is vital for the future of any company: will they recommend it to their friends? By the answer to it, you can judge which of them will become your client for life, and whose loyalty is short-lived and who will happily defect to your competitors. The answer to this simple question can reveal a lot about the future of a company. The book provides dozens of examples and a detailed methodology for calculating and assessing customer loyalty indicator.