He was one of the co-inventors of hyperkähler quotients, a hyperkahler analogue of Marsden–Weinstein reduction and the structure of Bihermitian manifolds. His research interests include supersymmetry, string theory and applications of generalized complex geometry, and with S. J. Gates, M. T. Grisaru, and W. Siegel, Rocek coauthored Superspace, or One thousand and one lessons in supersymmetry (1984), the first comprehensive book on supersymmetry.