This chapter begins with an examination of the origins of urban sustainability. We focus on the issues in relation to the themes of sustainability and development, setting the scene for further exploration of key topics, such as sustainable city, eco-city and eco-development. In this chapter, we also discuss the topic of eco-development based on its general challenges, implications and actor constellations. The three spatial levels of the built environment (city, neighbourhood/community and building) are introduced and discussed further, which are then followed up by detailed discussions on the topic of urban sustainability. This chapter concludes with a discussion on barriers of promoting eco-development in present.