The almost universal presence of water in our everyday lives and the very common' nature of its presence and properties possibly deflects attention from the fact that it has a number of very unusual characteristics which, furthermore, are found to be extremely sensitive to physical parameters, chemical environment and other influences. Hydrogen-bonding effects, too, are not restricted to water, so it is necessary to investigate other systems as well, in order to understand the characteristics in a wider context. Hydrogen Bond Networks reflects the diversity and relevance of water in subjects ranging from the fundamentals of condensed matter physics, through aspects of chemical reactivity to structure and function in biological systems.

J.E. Enderby At the last NATO-ASI on liquids held in Corsica, (August 1977), Professor de Gennes, in his summary of that meeting, suggested that the next ASI should concentrate on some specific aspect of the subject and mentioned explicitly ionic solutions as one possibility. The challenge was taken up by Marie-Claire Bellissent-Funel and George Neilson; I am sure that all the participants would wish to congratulate our two colleagues for putting together an outstanding programme of lectures, round tables and poster session. The theory which underlies the subject was covered by four leading authorities: J.-P. Hansen (Paris) set out the general framework in terms of the statistical mechanics of bulk and surface properties; H.L. Friedman (Stony Brook) focused attention on ionic liquids at equilibrium, and J.B. Hubbard considered non-equilibrium properties such as the electrical conductivity and ionic friction coefficients. Finally, the basic theory of polyelectrolytes treated as charged linear polymers in aqueous solution was presented by J.M. Victor (Paris)

The almost universal presence of water in our everyday lives and the very common' nature of its presence and properties possibly deflects attention from the fact that it has a number of very unusual characteristics which, furthermore, are found to be extremely sensitive to physical parameters, chemical environment and other influences. Hydrogen-bonding effects, too, are not restricted to water, so it is necessary to investigate other systems as well, in order to understand the characteristics in a wider context. Hydrogen Bond Networks reflects the diversity and relevance of water in subjects ranging from the fundamentals of condensed matter physics, through aspects of chemical reactivity to structure and function in biological systems.