Berkeley Prosopography Services (BPS) provides a new set of tools for prosopography - the identification of individuals and study of their interactions - in support of humanities research. Prosopography is an example of “Big Data” in the humanities, characterized not by the size of the datasets, but by the way that computational and data-driven methods can transform scholarly workflows. BPS is based upon re-usable infrastructure, supporting generalized web services for corpus management, social network analysis, and visualization. The BPS disambiguation model is a formal implementation of the traditional heuristics used by humanists, and supports plug-in rules for adaptation to a wide range of domain corpora. A workspace model supports exploratory research and collaboration. The BPS model of configurable heuristic rules facilitates interpretation by humanist researchers. The BPS assertion model enables researchers to assert conclusions or possibilities, allowing them to override automated inference, to explore ideas in what-if scenarios, and to formally publish and subscribe-to asserted annotations among colleagues, and/or with students.