Dave Barker-Plummer is a Senior Research Scientist at Stanford University's Center for the Study of Language and Information. He holds a Ph.D. from the Department of Artificial Intelligence atEdinburgh University. Since 1995 he has managed the Openproof project's work on educational software for teaching logic at the undergraduate level. He is the author of papers on automated reasoning, reasoning with diagrams, and architectures for heterogeneous reasoning. He co-edited the collection Words, Proofs and Diagrams and was program chair of the Diagrams 2006 conference. Dave has taught computer science and logic at Stanford, Swarthmore College and Duke University.