My research focuses on many aspects of high-redshift galaxy clusters. I am involved in a number of large optical/IR imaging surveys to create large samples of clusters up to redshift of 2. These provide cluster samples for projects in galaxy and cluster evolution and observational cosmology. These include spectroscopic surveys of cluster galaxies, the evolution and formation of clusters, the roles of environments in the evolution of galaxies, the morphology of galaxies in clusters, gravitational lensing, and the applications of galaxy clusters to cosmology. I also work on photometric redshift
techniques, and their applications to galaxy evolution studies involving large galaxy photometric catalogues.