Saskia Sassen's research and writing focuses on globalization (including social, economic and political dimensions), immigration, global cities (including cities and terrorism), the new networked technologies, and changes within the liberal state that result from current transnational conditions. In her research she has focused on the unexpected and the counterintuitive as a way to cut through established "truths." Her three major books have each sought to demolish a key established "truth". Thus in her first book, The Mobility of Labor and Capital (Cambridge University Press 1988), she showed how foreign investment in less developed countries can actually raise the likelihood of emigration; this went against established notions that such investment would retain potential emigrants.

In her second book The Global City (Princeton University Press 1991; 2^nd ed 2002) she showed how the global economy far from being placeless, has and needs very specific territorial insertions, and that this need is sharpest in the case of highly globalized and electronic sectors such as finance; this went against established notions at the time that the global economy transcended territory and its associated regulatory umbrellas. In her most recent book, Territory, Authority, Rights: From Medieval to Global Assemblages (Princeton University Press 2006; 2^nd ed. 2008), she shows that the foundational transformations afoot today take place largely inside core and thick national environments; this allows her to explain that some of the changes inside liberal states, most evident in the USA -- but also increasingly in other countries -- are not distortions or anomalies, but are the result of these foundational transformations inside the state apparatus. She shows how this foundational transformation hence consists not only of globalizing dynamics but also of denationalizing dynamics: we are seeing the formation of multiple often highly specialized assemblages of bits of territory, authority and rights that were once ensconced in national framings. Today these assemblages traverse global and national settings, thereby denationalizing what was historically constructed as national.

In addition to the three works described above, Saskia Sassen recently published A Sociology of Globalization (Norton 2007). She has also just completed a five-year project for UNESCO on sustainable human settlement, for which she set up a network of researchers and activists in over 30 countries. The results of this study are published as one of the volumes of the Encyclopedia of Life Support Systems (Oxford, UK: EOLSS Publishers). She recently edited Deciphering the Global: Its Spaces, Scales, and Subjects (Routledge 2006), a collection of her doctoral students' work, and co-edited Digital Formations: New Architectures for Global Order (Princeton University Press 2005). The latter is based on a multi-year project sponsored by the Social Science Research Council, through its Information Technology and International Cooperation Committee, which she chaired. Among other projects, she was involved with the 2006 Venice Biennale of Architecture, which for the first time in its history focused on cities; she wrote a lead essay for the Catalogue. There are new fully updated editions of two of her older books, Cities in a World Economy (3^rd ed. Sage/Pine Forge 2006), and The Global City (2nd. ed. Princeton University Press 2001). Her books have been translated into sixteen languages.