Manuel Castells has been a leading figure in urban studies since the 1970s and is widely acclaimed for combining Marxist theoretical thinking with practical policy proposals. As a social theorist, his particular focus on the spatiality of cities has led to him becoming very influential in urban geography as specifically evidenced by his two invited papers in TESG in 1993 and 2002. In this paper, we develop an ontological critique of Castells' employing the mainstream position that cities reflect the nature of the societies that encompasses them, whereas we consider cities as the makers of their encompassing society. The TESG papers are broadly reviewed by contrasting their governance/policy approach with Jane Jacobs' economics/development approach. This critique does not diminish our appreciation for Castells' contribution to urban studies, rather the ontological critique is used as a tool for providing clarity of scholarship, not another episode of academic squabbling in urban studies.