[The following excerpt was originally published as an introduction to the German edition of von Däniken's Gods from Outer Space in 1968.]
Erich von Däniken is not a scholar. He is an autodidact, which the dictionary defines as a man who is self-taught. Probably this helps explain the success his first book [Chariots of the Gods?] met with all over the world. Completely free from all prejudices, he had to demonstrate personally that his theses and theories were not unfounded and hundreds of thousands of readers were able to follow him along the adventurous road he took—a road that led into regions that were surrounded and protected by taboos.
Besides, his fearless questioning of all the previous explanations of the origin of the human race seems to have been long overdue. Erich von Däniken was not the first man who dared to challenge them, but his questions were more impartial, more direct and more audacious. In addition, he was able to say exactly what he wanted to say, unlike a professor, for example, who would have felt bound to take the opinions of his colleagues or the representatives of similar academic disciplines into consideration. What is more, he came up with some startling answers.
Men who bluntly ask bold questions that cast doubt on time-honored, accepted explanations have always been a nuisance and people have never been overfussy about how they silenced them. In the past their books were banished to secret libraries or put on the index; today people try to hush them up or make them look ridiculous. Yet none of these methods has ever succeeded in disposing of questions which concern the reason for our very existence. (pp. vii-viii)
Wilhelm Roggersdorf, "About Erich von Däniken," in Gods from Outer Space: Return to the Stars or Evidence for the Impossible by Erich von Däniken, translated by Michael Heron, Bantam Books, 1972, pp. vii-viii.