Final answer:
The phrase popularized by Scandinavian Airlines System President Jan Carlzon in his book is Moment of Truth.
Step-by-step explanation:
The phrase popularized by Scandinavian Airlines System President Jan Carlzon in his 1987 book of the same name is Moment of Truth.
In his book, Carlzon describes the critical moments when a customer interacts with a company, which he refers to as the 'moment of truth'. These moments can make or break the customer's perception of the company and have a significant impact on customer satisfaction and loyalty.
By focusing on these moments of truth and delivering exceptional service during these encounters, companies can create a positive customer experience and build strong customer relationships.