Using the "Parallel Lives" approach adopted by the Greek biographer Plutarch by contrasting the lives and research careers of two famous astronomers, Percival Lowell and Edward Emerson Barnard, the author creates a uniquely insightful work that combines biographical details with a history of the times. Both astronomers had wide-ranging interests, but at a time when fascination with Mars was at its peak, their differing observations and interpretations of surface markings on the red planet provided a particularly important focus of their work and illustrate their different approaches to astronomical observation and theory. This book provides comprehensive information about the lives and work of these two astronomers. The one was a Boston Brahmin from an influential and wealthy family who first established his reputation as a traveler and writer about the Far East and took up astronomy comparatively late. Possessed of private means, he was able to set up his own observatory in Flagstaff Arizona USA and devoted much of his time and energy to the study of Mars, finding evidence of a system of artificial irrigation canals designed and built by a brilliant, though dying, master race. The other grew up poor in Nashville, Tennessee, USA, worked his way up from a menial position in a photograph studio to become a successful discoverer of comets and a pioneer of wide-angle photography of comets and the Milky Way. He was an observer, first and foremost, and used the largest telescopes available at the time, including notably the great refractors at Lick Observatory in California and Yerkes Observatory in southern Wisconsin to see Mars more clearly and definitively than it had been before--and even anticipated modern spacecraft observations. The work of these two astronomers has become the stuff of legend.

They influenced astronomy during an era of rapid change when it was moving away from largely visual methods to photography and spectroscopy, and from domination by "Grand Amateurs" to professional astronomers staffing large observatories. The stories of their passionate attempts to understand the universe remain to fascinate and inspire even as rovers such as the recent Perseverance on Mars are examining the surface of the red planet at a resolution of which they never dreamed, while the European Space Agency's Gaia and NASA's James Webb Space Telescope are mapping the positions and motions the stars and dark nebulae of the Milky Way first recorded in Barnard's photographs a mere century ago. Anyone interested in the brilliant legacy of the past, and interested in learning how we came to know what we now know, will find this an absorbing and indispensable work.