http://www.cs.princeton.edu/~appel/
Does research on AutomatedTheoremProving and ProofCarryingCode.
Author of the book CompilingWithContinuations and of the books "ModernCompilerImplementation? in Java", "ModernCompilerImplementation? in ML" and "ModernCompilerImplementation? in C".
One of the developers of Standard ML of New Jersey [SmlNjLanguage], a compiler for the StandardMetaLanguage.