The paper discusses and analyzes the scientific search service Google Scholar(GS). The focus is on an exploratory study which investigates the coverage ofscientific serials in GS. The study shows deficiencies in the coverage andup-to-dateness of the GS index. Furthermore, the study points up which Webservers are the most important data providers for this search service and whichinformation sources are highly represented. We can show that there is arelatively large gap in Google Scholars coverage of German literature as wellas weaknesses in the accessibility of Open Access content.Keywords: Search engines, Digital libraries, Worldwide Web, Serials,Electronic journals