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For millenia humans have considered Mars the most fascinating planet in our solar system. We’ve watched this Earth-like world first with the naked eye, then using telescopes, and, most recently, through robotic orbiters and landers and rovers on the surface.

Historian William Sheehan and astronomer and planetary scientist Jim Bell combine their talents to tell a unique story of what we’ve learned by studying Mars through evolving technologies. What the eye sees as a mysterious red dot wandering through the sky becomes a blurry mirage of apparent seas, continents, and canals as viewed through Earth-based telescopes. Beginning with the Mariner and Viking missions of the 1960s and 1970s, space-based instruments and monitoring systems have flooded scientists with data on Mars’s meteorology and geology, and have even sought evidence of possible existence of life-forms on or beneath the surface. This knowledge has transformed our perception of the Red Planet and has provided clues for better understanding our own blue world.

Discovering Mars vividly conveys the way our understanding of this other planet has grown from earliest times to the present. The story is epic in scope—an Iliad or Odyssey for our time, at least so far largely without the folly, greed, lust, and tragedy of those ancient stories. Instead, the narrative of our quest for the Red Planet has showcased some of our species’ most hopeful attributes: curiosity, cooperation, exploration, and the restless drive to understand our place in the larger universe. Sheehan and Bell have written an ambitious first draft of that narrative even as the latest chapters continue to be added both by researchers on Earth and our robotic emissaries on and around Mars, including the latest: the Perseverance rover and its Ingenuity helicopter drone, which set down in Mars’s Jezero Crater in February 2021.

Join today’s search for signs of alien life in fossil remains from prehistoric Mars, an Earth-like world that glittered with rivers, lakes, and deep blue seas.

Billions of years ago, there was another Earth in our solar system: the temperate and blue-streaked world of ancient Mars. Today, the rocky ruins of that lost world offer our best hope of finding signs of alien life. In How to Find a Martian, astrobiologist and paleontologist Sean McMahon argues that we may soon find fossils on Mars—perhaps even in our lifetime.

There are now thousands of astrobiologists around the world, using the tools of modern science to answer some of the most profound, intellectually exciting questions that have ever been asked: What is life? How does it evolve and proliferate across vast spans of space and time, and what forms might it take on alien worlds? The search for life on Mars is a mainstay of this research program, and it has never been more advanced, more sophisticated, or better funded than it is today. Although scientists have not yet found fossils on Mars, astrobiologist Sean McMahon says, we have at least learned how to find them. We now know which regions and landscapes on Mars could once have supported life and preserved its remains in rocks and minerals. We know how the remains of living organisms can end up woven into the texture of ancient rocks, transmuted into minerals or transcribed into the subtle language of fossil carbon molecules. But we have also learned to be cautious—and not to be fooled when non-living nature imitates the patterns of life. 

Accessibly explaining trailblazing ideas and findings in astronomy, geology, microbiology, and paleontology, McMahon makes a persuasive and alluring case that we have the tools, ideas, methods, and missions to find past life on Mars.