This chapter summarizes state failure research, responds to critics of the research agenda, and synthesizes both the work and its criticisms to propose an alternative methodology for analyzing state fragility: complex societal-systems analysis. It also summarizes recent innovations in the measurement of state fragility and failure, and review studies of state failure as both a cause and effect of other cross-national phenomena, such as organized crime, trafficking, and terrorism. Although the term "state failure" did not enter the mainstream academic vernacular until the early 1990s, recognition of the unique problems faced by societies with ineffectual states began during the Cold War. The concept of state failure combines two research streams that had previously remained largely separate in Western thinking: state-building and economic development. The US government's State Failure Task Force was created in October 1994 in response to a 1994 request from senior policymakers to design and carry out a study on the correlates of state failure.