This book is a record of the proceedings of a conference on portals and gateways to cities from the perspective of sustainable urbanization. The conference was held on 19 May 2017 at UN Headquarters in New York City and was co-sponsored by the Consortium for Sustainable Urbanization (CSU), UN-Habitat, and the New York Chapter of the American Institute of Architects. The book offers a variety of physical and virtual portal and gateway concepts and designs as a means to illustrate the metrics for successful future design, financing, construction, and management of sustainable portals to urban areas.