We describe a new paradigm for performing search in context. In the IntelliZap system we developed, search is initiated from a text query marked by the user in a document she views, and is guided by the text surrounding the marked query in that document ("the context"). The context-guided information retrieval process involves semantic keyword extraction and clustering to automatically generate new, augmented queries. The latter are submitted to a host of general and domain-specific search engines. The results are then semantically reranked, again, using context. It is our belief that letting context guide the search provides a better match to the user's current needs than just relying on the user's fixed personal profile. Our results show that using context to guide search effectively offers even inexperienced users an advanced search tool on the Web.