This volume documents the progress made in the design of complex artificial systems and in the study of intermolecular forces and interactions. It is possible, using appropriate strategies based on building blocks, to obtain very large supramolecular arrays containing several hundered atoms, where specific sites are occupied by the desired chemical functions. Such arrays can be used for such things as molecular recognition, self-organization, self-replication, selective reactivity, selective catalysis, photoinduced energy and electron transfer, signal processing, information storage and drug delivery.

The first NATO Science Forum was held in Biarritz in September 1990. This Taormina Conference is the second in a series that we wish to be a long one and I believe that it has equalled the success of its predecessor. In setting up these meetings the NATO Science Committee wanted to gather leading experts to review fields of strong present interest. It was intended that presentations and discussions should pay special attention to potential developments. This "forward look" is indeed precious to us in mapping out the evolution of our Science Programme but more importantly, it is an essential part of the progress of Science. I believe that NATO, being able to bring together eminent scientists from both sides of the Atlantic, is in a priviliged position to provide this service to our Scientific Community. It was only proper that Chemistry should be one of the first areas to be targeted: a central science with many rich borders touching on other disciplines, it deserved the full attention of our Committee. In its vast domain, among many possible topics, the present one was carefully selected and its choice resulted from an extensive consultation of many leading chemists. The large fraction of replies which pointed to Supramolecular Chemistry left us with little doubt about the timeliness of a Forum in this area and the strong interest attached to it.