As an introduction to the second paper of this issue, where the aims and methods of the Portuguese malacological mapping survey aretireated, the rather recent history of the European Invertebrate Survey (E.I.S.) and the preceding events that led to the now adopted procedures are briefly described. The meetings held at successive malacological congresses in connection with Unitas Malacologica for that this result to be achieved are mentioned, and the role of national societies in promoting and furthering surveys of the several faunistic groups is evidenced