My research concerns how the changing geopolitical positioning of the post-Yugoslav states has impacted on the lives and prospects of students and researchers in the natural sciences. The main focus is on scientists' experiences and self-reporting, both of the situation at present and during the nineties, when scientific operations and scientists' lives were disrupted by war and in the case of Belgrade, Serbia, UN sanctions against science. My fieldwork is centred on participant ethnography based at an institute in Belgrade, Serbia (the Belgrade Astronomical Observatory). However, throughout the thesis I trace and make connections between numerous other institutes and networks, as well as drawing on interview material and ethnography completed with students in Belgrade and Zagreb, Croatia. I analyse in particular on the impact of the recent wars, attempted 'democratic transition' and the current European economic crisis. My main argument is that whilst neoliberalisation and social changes over the past forty years have created opportunities for scientists globally, these opportunities were not evenly distributed. For scientists committed to living and working in the former Yugoslav region, these changes were often, but not always experienced as a hindrance; particularly as seen through the lens of reperipheralisation, which strongly relates to the context of war and recent scientific isolation. In the introduction and first chapter of the thesis, I detail the background in light of which ethnographic insights in the later chapters make sense. I then examine how scientists' practices and experiences reflect, relate to, shape and have been shaped by not only post-Yugoslav discursive hegemonies (chapter two), but also disciplinary changes (chapter three), local academic hierarchies and conventions (chapter four), the socialist legacy and attempted neoliberal 'transition' (chapters two, three, four and five), academic traditions (chapter six) and national cosmology (chapters two and six). The thesis also attempts to make an original contribution to anthropological studies of science, in particular engaging with Latour and Woolgar's (1986) work on credibility (chapter three), literature on science and its publics (chapter five) and the historiography of science (chapter six). The thesis also draws heavily on anthropological theory from other traditions in the discipline, including Marxist anthropology and theories of hegemony (chapter two), Bourdieu's (1984) work on education (chapters two and four), Verdery's (1995) analysis of cultural politics under socialism (chapters three and five) and exchange theory, including Graeber's (2011) work on debts and indebtedness (chapter six). One key theoretical claim advanced through the ethnographic material is that an anthropological study working with scientists in what Blagojevic (2010) terms the 'semiperiphery', and where a series of violent wars had recently took place, warrants a human focus, namely on the scientists and how they collectively dealt with and coped with disruption to their work and the reorganisation of their social worlds.