The author describes the earth etchings of Nazca, and traces the history of the theories about their origin and purpose. The solution he puts forward is that at some point in the past, extraterrestrials landed at Nazca in their space machines.

With his 1970's blockbuster "Chariots of the Gods," Erich von Dä niken challenged the scientific community to open their minds to new possibilities: "Suppose the ancient supernatural beings of traditional religions are no mere figments of mythological imagination, but are arrivals from outside our planet. Now, the world-famous author continues his controversial research into extraterrestrial visitation. Von Dä niken's latest offering draws on mountains of new evidence of unexplained phenomena, from UFO sightings and alleged abductions to archaeological discoveries of unearthly-looking beings, as well as research on human genetics that casts light on our origins outside the solar system. Armed with a collection of color photos, charts, and illustrations, Von Dä niken re-examines ancient texts and cave drawings of strange beasts with no known counterparts of the times, to support his theory that they could have been created by aliens, and to form an audacious conclusion: "We are much on the minds of other life-forms in the universe."