Biomolecular research has so many facets that it is impossible to cover all important aspects of this highly interdisciplinary field in a single book. However, by definition, generic physics-based approaches have the potential to introduce concepts and tools that enable systematic and consistent investigations of complex systems, even in cases where these systems (cell systems, individual cells, molecular composites, biomolecules, solvent molecules, etc.) do not seem to possess any similarities. The physical concepts are based on quantum and classical theories, intertwined by the basic theory of complexity under the influence of thermodynamic effects: statistical mechanics. All biological, biochemical, and biophysical processes are caused by the interaction of basic units such as atoms, chemical groups, molecules. None of those processes can be thought of as being disconnected from cooperative ordering (or disordering) effects, and for our understanding of these effects on nanoscopic to mesoscopic scales only the basic theory of statistical physics is available to unravel the macroscopic consequences of these processes. The macroscopic description is what we call thermodynamics.

The currently most successful theoretical tool to investigate and to analyze thermal fluctuations statistically is the computer simulation. The computer has not replaced the human brain, but it has changed the way we deal with complex problems.