A half a million glass photographic plates hold the only visual record of the night sky between 1885 and 1992. This dazzles me and I'm not an astronomer. It dazzles me even more to learn that a group of dedicated women (mostly unpaid) spent decades attending to these glass slides with utmost dedication well before women were allowed to attend Harvard. These women helped count the stars, helped astronomers learn what the stars are made of, created the classification system astronomers still use, and inadvertently helped measure our Universe. I didn't have to be an astronomer to love this book, and neither do you.