his most recent books were "the global migration crisis: challenge to states and to human rights" (harpercollins, 1995 ); "threatened peoples, threatened borders: world migration and us policy" (co-editor, w. norton, 1995); "the new geopolitics of central asia and its borderlands" (co-editor, indiana university press, 1994); "the state and social transformation in afghanistan, iran and pakistan" (co-editor, syracuse university press, 1994); and "international migration and security" (editor, westview press, 1993).