Author Mark Kaufman believes that before the end of the century, maybe well before, scientists will have determined that life exists elsewhere in the universe, and his book makes a fascinating and compelling case for it. Before they can do that however, scientists will have to determine exactly what life is, a question that is surprisingly hard to answer because it is not always clear what is alive and what is not. One example is the case of desert varnish, an extremely slow growing patina found on desert rocks that may be showing properties of life. Or maybe not, that’s still being researched. The more scientists learn about life on Earth, the stranger it seems. It used to be taken as scientific gospel that all forms of life reproduce regularly, need an energy source, and depend on having an environment that isn’t exceedingly hot, cold, acidic, alkaline, or salty, and isn’t under crushingly high pressure or full of radiation, but living things have been found in all of these circumstances. Extremophile life forms manage just fine in scalding hot hydrothermal ocean vents, highly acidic rivers, arsenic filled lakes, glacial ice, clouds high in the sky, and rocks that are miles underground. Finding life in these almost other worldly places may mean life can exist in other harsh seeming environments, like under the Martian surface or in the icy oceans of Jupiter’s moon Europa. It turns out that Mars was much more habitable than Earth in the long ago days when the Earth was recovering from a collision with another planet that broke off what is now our moon. Mars became the barren landscape it is now after it somehow lost its magnetic field and atmosphere, but if some form of life was already established it may still survive deep underground, since scientists have found that life exists in similar conditions on Earth.The elements that are needed for life on Earth, which include carbon, oxygen, nitrogen and hydrogen, are found all over the universe, so scientists are aiming strong telescopes at distant stars looking for planets that might be able to support life as we know it, or maybe life as we’ve never conceived of it. The nebulas that form stars produce complex carbon molecules and these may be seeding any nearby planets with the building blocks of carbon based life.Kaufman is confident that there is life elsewhere in the universe, but he does a thorough job presenting the conflicting opinions and many unsolved issues of the extraterrestrial life question, including the controversies surrounding the 1976 Viking mission to Mars and whether the Muchison meteorite from Austraila shows evidence of otherworldly organic carbon. The last chapter covers the moral, religious and ethical implications of discovering that we may be sharing the universe with other, possibly intelligent, living beings. What obligations would we have to such creatures? What would they mean for the world’s religious beliefs? These issues are part of an ongoing discussion by ethicists, philosophers, and religious leaders, including the Vatican. If you follow news reportage about extremophiles, exoplanets and the search for life, this book will connect the dots and provide context to stories as recent as the “Goldilocks” planet, the new revelations about the famous “primordial soup” experiments, and the microbes found with high levels of arsenic in Mono Lake, California. First Contact is so irresistibly interesting I found myself reading the best parts aloud to whoever happened to be around me at the time.