Biophysics deals with biological systems, such as proteins, which ful?ll a va- ety of functions in establishing living systems. While the biologistuses mostly a phenomenological description, the physicist tries to ?nd the general c- cepts to classify the materials and dynamics which underly speci?c processes. The phenomena span a wide range, from elementary processes, which can be induced by light excitation of a molecule, to communication of living s- tems. Thus, di?erent methods are appropriate to describe these phenomena. From the point of view of the physicist, this may be Continuum Mechanics to deal with membranes, Hydrodynamics to deal with transportthrough vessels, Bioinformatics to describe evolution, Electrostatics to deal with aspects of binding, Statistical Mechanics to account for temperature and to learn about the role of the entropy, and last but not least Quantum Mechanics to und- stand the electronic structure of the molecular systems involved. As can be seen from the title, Molecular Biophysics, this book will focus on systems for which su?cient information on the molecular level is available. Compared to crystallizedstandard materials studied in solid-state physics, the biological systems arecharacterizedby verybig unit cells containingproteinswith th- sands of atoms. In addition, there is always a certain amount of disorder, so that the systems can be classi?ed as complex. Surprisingly, the functions like a photocycle or the folding of a protein are highly reproducible, indicating a paradox situation in relation to the concept of maximum entropy production.