DESC: Many of us have scanned the night sky wondering: Is there life beyond the earth? And, if there is, could they be looking for us, too? Our quest for extraterrestrial life is widespread and entrenched. The SETI program searches for radio signals from the cosmos. NASA seeks and studies conditions that make life in outer space possible. We now know that planetary systems similar to ours exist and that our particular environment may not be the only one that can support life. It's not just UFOs and superstition; the search for alien life is the stuff of serious science. Using the famous Drake equation, Aczel presents evidence from across the sciences, fitting together the elements that make life possible. And then, with a bit of brilliant math, Aczel, an expert in statistics and probability, shows that the probability is 1: intelligent extraterrestrial life exists.