Speculation about our spaceships, landing on other inhabited planets should be matched, asserts Von Daniken with revolutionary elan, by exploration of the possibility that he earth has already played host to interplanetary callers: ""I claim that our forefathers received Visits from the Universe in the remote past, even though I do not yet know who these extraterrestial intelligences were or from which planet they came."" Although he hardly expects to make instant, converts, Von Daniken does indeed aim to be taken seriously, and he marshals a sufficient weight of respectable, vaguely corroborative opinion to maintain some credibility (but nothing approaching gut certainty). The proof positive is an interesting collection of archaeological, astronomical, and historical facts ranging from flimsy to provocative, a catch, all of prehistoric puzzles and cosmic curiosities. Primitive people in premature possession of sophisiticated knowledge and techniques (including Thor Heyerdahl's Easter Islanders) provide evidence of assistance from advanced outsiders, while numerous references in myth and religion to flying gods appearing in the-flesh and fertilizing earthly females suggest a more direct intervention. There are favorable evaluations of UFO-sightings, thought .transference, and the new disciplines of exobiology and futurology, yet another spirited defense of the space program, and a proposal for a ""Utopian archaeological year"" to substantiate the author's suspicions. Though 2001 Space oddities do not by any means a theory prove; the book has a distinct conversation-piece appeal (""Was God An Astronaut?"").