Determination of liquid water structure coordination numbers for ions and solvation for biological molecules From the foreword: The structure of liquid water and the solvation of ions and molecules represent an active field of past and current research we have stressed in particular the new quantum mechanical developments that constitute the conceptual base for the recent advancements in this field. For this reason in the first part (concerning quantum mechanical techniques) we have pointed out with a variety of examples the large amount of information embodied in quantum mechanics that is often ignored either because not too important in discussing small molecular systems or because relatively too new.