Acknowledgements
MJB acknowledges the kind hospitality of the Aspen Center for Physics, and the anonymous referees whose extensive knowledge of the subject has helped fill in the gaps in his understanding. Extensive use was made of both the arXiv pre-print server and the ADS system. Previous versions of this work were supported by NASA EPSCoR grant NCCW-0058, Montana EPSCoR grant NCC5-240, NASA Cooperative Agreement NCC5-579, and NASA APRA grant NNG04GD52G. This current version has been supported by the Center for Gravitational Wave Astronomy, which is supported by NASA Grant NNX09AV06A and NSF award #0734800.JMBD is supported by the European Gravitational Wave Observatory through VESF grant EGO–DIR-50-2010. He also wishes to acknowledge financial support provided by the University of Texas at Brownsville for a visit during which work on the most recent edition of this review was initiated.