For cities to confront the challenges of fossil fuel depletion, increasing energy costs and rapid climate change, it is vital to develop and implement urban energy management solutions for a sustainable future. This publication for the United Nations Human Settlements Programme (UN Habitat) is a training companion developed originally for training courses at the International Urban Training Centre in the Republic of Korea. This source-book addresses sustainable urban energy solutions from a system’s perspective in a three-step process, including energy conservation, energy efficiency and renewable energy.