A belief in life on other planets is nothing new, but as this installment in the Science Fact or Science Fiction? series (6 titles) makes clear, it might actually be something very old. Some people think that aliens are woven into the architecture, stories, and technologies of our ancient past. In measured, nonsensationalized text, beginning with the Nazca Lines in Peru (drawn to be viewed from above, long before human air travel was possible), the text-heavy book explains how aliens may have visited earth long ago. It continues to point out ways in which people see extraterrestrial presence in our history (monsters in Greek mythology; the seemingly impossible creation of Egyptian pyramids), before explaining how scientists have debunked these theories. Open-minded but still practical, this is a balanced exploration of a high-interest topic.