Hello James, the Surface books do not come with integrated RealSense cameras. You must purchase a peripheral RealSense camera in order to benefit from RealSense capabilities on a Surface PC. You can purchase a RealSense camera from http://click.intel.com or from a number of RealSense peripheral vendors.
I hope this answers your question. If you would like further assistance, please post your question in the RealSense Community. This forum in the Intel Developer Zone will soon be archived and all support will be handled in RealSense Community.
Intel Customer Support