A *(person) who is a _(research professor|http://www.cis.upenn.edu/~bcpierce/) at the University of Pennsylvania, working in _(type) theory, _(concurrency) and _(object-oriented) theory. He is the author of several interesting books and _(dozens of papers|http://www.cis.upenn.edu/~bcpierce/papers/) on type theory and _(programming language)s.