This document provides an overview of intelligent cities and their conceptualization. It discusses two driving forces behind the new type of urban space in the 21st century: 1) an innovation-led economy and knowledge-based society where R&D, knowledge, and innovation drive city development, and 2) a new digital spatial layer that creates broadband networks and applications to connect cities locally and globally. It then examines the innovation-led economy in more detail, outlining the local innovation systems, clusters, institutions, and processes that support knowledge-based cities.