This title specifically traces the impact of Einstein's ideas on astronomy, including the way we interpret observations of stars and galaxies. This title: includes comments from principals in important discoveries, illuminating the processes behind these results; presents many applications of relativity that have not been shown in earlier popular-level books and illustrates how deeply physics permeates the way we interpret many astronomical phenomena; highlights light-travel delays in cosmic jets, using gravitational lensing to trace cosmic mass distribution; includes illustrations that employ new and archival data from ground- and space-based observatories.