I've a strong interest in the "ancient astronauts" theory, and this is book is arguably the one that started the whole thing. But having just re-read it after many years, I was left feeling distinctly under-impressed. The book is rambling, disjointed, repetitive, and contains hundreds of unanswered questions. True, von Däniken claims that his purpose was to merely raise the questions rather than provide answers, but it does leave you feeling that you've only read half a book. The way he presents his theories is often sketchy and vague. He doesn't care to consider in any depth what the *purpose* of the extraterrestrial visitors might have been, he is content mainly to claim evidence of their presence. Some of his predictions, such as the human Mars landings, are way off the mark. Moreover, there are many ideas presented in the book but little actual science. His constant pointing out that the American space programme was for a long time based mainly on the work of Nazi scientists is, however, amusing.
The new introduction written by the author is almost laughable. Aside from attempting to riposte a few very specific criticisms of some of his claims, it adds very little to the book.
I'm giving this book 3 stars because of its significance - it set the ball rolling. But if you want a much more detailed, well-rounded, well-researched, thoughtful and better-written survey of our possible ET origins and links, including considerable coverage of the important Sumerian mythology, you'd do much better to read William Bramley's "The Gods of Eden".