Current biological research demands the extensive use of sophisticated mathematical methods and computer-aided analysis of experiments and data. This highly interdisciplinary volume focuses on structural, dynamical and functional aspects of cellular systems and presents corresponding experiments and mathematical models. The book may serve as an introduction for biologists, mathematicians and physicists to key questions in cellular systems which can be studied with mathematical models. Recent model approaches are presented with applications in cellular metabolism, intra- and intercellular signaling, cellular mechanics, network dynamics and pattern formation. In addition, applied issues such as tumor cell growth, dynamics of the immune system and biotechnology are included.