This document summarizes a book about managing change in IT outsourcing from the service provider perspective. It discusses research showing that providers often struggle with sustainable performance for clients over time. The book examines factors that influence sustainable performance, such as organizational structure, capabilities, and adapting to changing client needs. It presents findings on issues during the transition phase, benefits of customizing structures while standardizing back-office functions, the importance of client knowledge, and keys to dynamic fit and long-term adaptability. Measuring holistic performance over multiple years and including the client perspective were found to positively impact sustainable results.