My specialty is algebraic number theory. I study unit and ideal class groups of number fields, the Galois theory of extensions with restricted ramification, the arithmetic of elliptic curves, and special values of L-functions. My past PhD students are Mairead Greene (Rockhurst University) and Laura Hall-Seelig ( Merrimack College). I'm currently working on a monograph on asymptotically good families of curves, codes, number fields, and graphs.