Water existed on this planet long before life evolved. The developing chemistry of life processes therefore had to take account of the eccentric physical properties of the universal solvent medium. Water participates in most biochemical reactions, viz. condensation, hydrolysis, oxidation and reduction, either as a reactant or a product. The conformational properties of complex organic molecules and their interactions are also affected by the stereochemistry of hydration effects which are dominated by the tetrahedral structure of the H2O molecule and its hydrogen-bonding capability.

The influence of hydration on macromolecular structures is a subject of intense study by experimental, theoretical and, of late, computer simulation methods. It is very much a case of running before we can walk. The hydration interactions of monomers and oligomers have been neglected, although they can probably shed light on some important aspects of macromolecular behaviour.

This volume is devoted to the solution behaviour of the molecules of life: lipids, nucleotide bases, amino acids and sugars. Theory is confronted by experiment, and comparisons are made between the properties of molecules in crystals and in solution. The diversity in the various types of molecular behaviour is impressive, with hydrophobic effects dominant in controlling lipid interactions, while complex three-dimensional hydrogen bonding patterns regulate the interactions between sugars and also their conformational equilibria in solution.

The general conclusion is that molecular shapes and interactions in solution, and presumably also in vivo, are governed by weak, non-covalent effects, some spherically symmetrical and others orientation-specific.