The Lifelong Learning Imperative (LLI) project was initiated to assess current practices in lifelong learning for engineering professionals, reexamine the underlying assumptions behind those practices, and outline strategies for addressing unmet needs. The LLI project brought together leaders of U.S. industry, academia, government, and professional societies to assess the current state of lifelong learning of engineers; to examine the need for, and nature of, lifelong learning going forward; and to explore the responsibilities and potential actions for the primary stakeholders.