This volume comprises the proceedings of a NATO Advanced Study Institute held at Geilo, Norway, 24 March - 3 April 2003, the seventeenth ASI in a series held every two years since 1971. The objective of this ASI was to identify and discuss areas where synergism between modern physics, soft condensed matter and biology might be most fruitful. The main pedagogical approach was to have lecturers focussing on basic understanding of important aspects of the relative role of the various interaction- electrostatic, hydrophobic, steric, conformational, van der Waals etc. Soft condensed matter and the connection between physics and biology have been the themes of several earlier Geilo Schools. A return to these subjects thus allowed a fresh look and a possibility for defining new directions for research. Examples of soft materials, which were discussed at this ASI, included colloidal dispersions, gels, biopolymers and charged polymer solutions, polyelectrolytes, protein/membrane complexes, nucleic acids and their complexes. Indeed, most forms of condensed matter are soft and these substances are composed of aggregates and macromolecules, with interactions that are too weak and complex to form crystals spontaneously. A characteristic feature is that small external forces, slight perturbations in temperature, pressure or concentration, can all be enough to induce significant structural changes. Thermal fluctuations are almost by definition strong in soft materials and entropy is a predominant determinant of structure, so that disorder, slow dynamics and plastic deformation are the rule. Hence the phrase ‘soft condensed matter’ has been coined.