Mark Walsh's research deals with the relationship between curvature and topology on smooth manifolds. This is a rich subject combining techniques from Geometry, Topology and Analysis. In particular, Walsh is interested in metrics of positive scalar curvature (psc-metrics). Although the problem of whether or not a particular smooth manifold admits a psc-metric has been studied extensively, relatively little is known about the topology of the space of psc-metrics on a given manifold, or it's corresponding moduli spaces. Much of Walsh's work involves the creation of tools for constructing interesting families of psc-metrics. This has helped show, for example, the non-triviality of certain higher homotopy groups of the moduli space of psc-metrics.