The symposium 'Sleepers, Moles, and Martyrs: Secret Identifications, Societal Integration, and the Differing Meanings of Freedom' held in Reinhausen, 2002, formed the basis of this issue of Ethnologia Europaea. Occasioned by the social, political and mass media discourses after the bombings of New York's World Trade Center on September 11, 2001, an interdisciplinary group of scholars came together to explore the connotations and implications of the term 'sleeper'. The biographies of terrorist perpetrators are but one of many permutations of sleeper-like phenomena in late modern polities. Clandestine operatives of the state are sleepers, and both willing and unwilling victims of terrorism are discursively transformed from sleepers into martyrs. Starting with analyses of the discourses about sleepers in Part I-their historical antecedents, narrative emplotment, and semantic differentiation-Part II turns to the hidden or unspoken of aspects of the state, the challenge of fundamentalist terrorism to the modern political project and the tensions between neighbourly discourse, public display and the state. Part III juxtaposes changing depictions of Shiite martyrdom with the violence done to the term 'martyr' within the Israeli-Palestinian conflict. In Part IV, cultural secrets encoded in memorials and public silences in academic discourse are addressed. The different cases assembled offer comparative materials and perspectives from the USA, France, the Netherlands, Pakistan, Spain, Iran, Israel, Istria and Sweden.