Most of my work is in hyperbolic geometry and low-dimensional topology, although I am also interested in combinatorial, measurable and geometric group theory, and Gromov-style Riemannian geometry. Here is my CV.
I co-organize the Geometry/Topology seminar at Boston College.
I am working on an online book Geometry in Two Dimensions that is suitable for students with only a multivariable calculus background. Currently, it discusses Euclidean, spherical and hyperbolic geometry, and touches on additional topics like scissors congruence, isoperimetric inequalities, and tilings.