The historical and social implications of the telescope and that instrument’s modern-day significance are brought into startling focus in this fascinating account. When Galileo looked to the sky with his perspicillum, or spyglass, roughly 400 years ago, he could not have fathomed the amount of change his astonishing findings—a seemingly flat moon magically transformed into a dynamic, crater-filled orb and a large, black sky suddenly held millions of galaxies—would have on civilizations. Reflecting on how Galileo’s world compares with contemporary society, this insightful analysis deftly moves from the cutting-edge technology available in 17th-century Europe to the unbelievable phenomena discovered during the last 50 years, documenting important astronomical advances and the effects they have had over the years.