Clouds have been observed at great heights in the polar regions for a century or more. Recently this series of ground-based observations has been greatly extended by limb viewing satellite systems. A major result has been the discoveries of more pronounced, more pervasive cloud phenomena extending all the way across the poles themselves. This review focuses on the results of more than three years of observation and analysis of polar mesospheric (or noctilucent) clouds by the Solar Mesosphere Explorer satellite and team. We present an updated climatology of cloud radiances and occurrence frequencies using a conservative background removal process. We also review a quite recent study of cloud heights and show how relatively little variation occurs on all time scales investigated, except perhaps for differences between the hemispheres themselves.