Recounts the story of Radcliffe-educated Henrietta Swan Leavitt, who in the face of ill health and progressive hearing loss discovered a new law that enabled astronomers to use variable stars in order to measure the universe, a finding that solved a key scientific mystery and enabled important breakthroughs. Reprint.

SWEEPER IN THE SKY is the biography of Maria Mitchell, the first woman astronomer in the U.S. At the age of 28, Mitchell discovered a comet in 1847 and was awarded a gold medal by the King of Denmark for her discovery. When Vassar College opened in 1865, Mitchell became its first astronomy professor and observatory director. For 23 years, Mitchell presided over a rigorous astronomy program at Vassar College. She gained national fame as a pioneering teacher, noted for her progressive ideas and her emphasis on the importance of research. In subsequent years, more than two dozen of her students were featured in "Who's Who in America." Mitchell served as a founder and president of the Association for the Advancement of Women. This special commemorative edition of SWEEPER IN THE SKY -- marking the 150th Anniversary of Maria Mitchell's discovery of a comet, as well as the opening of the Class of 1951 Observatory at Vassar College -- features an unabridged reprint of Helen Wright's classic 1949 biography, plus archival photographs, a new preface and epilogue by Vassar astronomy professors, and a new "For Further Exploration" section, including related web sites on the Internet.