Software product-line engineering is one of the few approaches to software engineering that shows promise of improving software productivity by factors of 5 to 10. There are still few examples of its successful application on a large scale, partly because of the complexity of initiating a product-line engineering project and the many factors that must be addressed for such a project to be successful. This tutorial draws on experiences in introducing and sustaining product-line engineering in Lucent Technologies and in Avaya. The objective is to convey to participants the obstacles involved in transitioning to product line engineering and how to overcome such obstacles, particularly in large software development organizations. Participants will learn both technical and organizational aspects of the problem. Participants will leave the tutorial with many ideas on how to introduce product line engineering into an organization in a systematic way.