Rather than a guidebook or a history of the ruins, this book presents a theory that attempts to explain the meaning of Machu Picchu and the reasons why it was built in such a dramatic location. This pursuit leads to a reexamination of the possible significance of some of the site’s key architectural features. Despite the book’s somewhat academic approach and its limited distribution in Peru, I have been agreeably surprised at how widely it has come to be read. I am pleased to be able to reissue it in this North American edition, with a few additions to bring it up to date.