"We've all asked ourselves the question. Looking up at the night sky, it's almost impossible NOT to wonder: Are we alone in the universe? In [this book], Space.com senior writer Dr. Michael Wall treats that question as merely a jumping-off point. He considers, for instance, the myriad of questions that would arise once we do discover life beyond Earth (an eventuality which, top NASA officials told Dr. Wall, is only drawing closer). From the unexpected--do...