SNOLAB is an underground science laboratory specializing in neutrino and dark matter physics. Located 2 km below the surface in the Vale Creighton Mine located near Sudbury Ontario Canada, SNOLAB is an expansion of the existing facilities constructed for the Sudbury Neutrino Observatory (SNO) solar neutrino experiment. SNOLAB follows on the important achievements in neutrino physics achieved by SNO and other underground physics measurements. The primary scientific emphasis at SNOLAB will be on astroparticle physics with the principal topics being:Low Energy Solar NeutrinosNeutrinoless Double Beta DecayCosmic Dark Matter SearchesSupernova Neutrino SearchesThese are areas of research where the experiments require great depths to reduce cosmogenic backgrounds. They also require extreme levels of cleanliness to reduce environmental radiological backgrounds to the levels necessary for these very sensitive measurements. SNOLAB achieves these goals by being located 2 km underground and by having the entire laboratory constructed as a single large clean room (class 2000).While particle astrophysics is the principle focus for SNOLAB, there is a growing interest in other scientific fields to exploit deep underground laboratories. In particular, there has been interest expressed in the fields of Seismology and Geophysics interested in precision, long term measurements at depth and in the field of Biology where there is a growing interest in deep under ground life.