Modern efforts on digitizing electronic books focus on preserving authentic "spatial" representation of the original sources. The new format requires new tools to help users to access, process, and make sense of digital information. This paper presents an approach which assists users of these new "spatial" sources by giving them a combination of annotation and social navigation support. This approach is currently fully implemented and under evaluation in a classroom study. Categories and Subject Descriptors H.5.4 [Information Interfaces and Presentation]: Hypertext/Hypermedia