An international conference on ‘archaeo-astronomy’ is an interesting experience for a historian of astronomy of the traditional school. Even if he is somewhat acquainted with the literature on the subject, and perhaps to some extent has also used it for teaching purposes, he must feel very much an outsider. He is familiar only with certain types of sources in the form of documents or instruments and not used to the strange array of material presented here in evidence of a startling hypothesis, of a prehistoric prelude to an historical account which until now has begun with the earliest written records. The immediate effect is a feeling of perplexity or confusion which only gradually gives way to a set of more structured impressions. Certain parts of the material seem to indicate possible fields in which the possibility of fruitful research cannot be dismissed without further investigation. A number of more or less obvious pitfalls reveal themselves as almost inevitable consequences of the very nature of the material evidence. Furthermore, the dangers connected with any kind of interdisciplinary study become clearly apparent. And last, but not least, one becomes increasingly aware of a series of methodological questions which must be answered if the whole subject is to be salvaged from the rocks, lurking under the surface in the form of arbitrary assumptions, vicious circles, and unjustified inferences.