I am an algebraist interested in a broad range of areas. I've worked on semigroups, geometric group theory, representation theory, self-similar groups (aka automaton groups), profinite groups and random walks on semigroups and groups. I've been particularly interested in interactions between these areas and Computer Science and am fond of algorithmic questions. Recently, I've been dabbling with operator algebras associated to etale groupoids and inverse semigroups.