The physical foundations and processes in living matter are the subjects of biophysics. Biological physics combines methods and approaches from various fields and applies both theoretical and experimental concepts from many scientific disciplines. Important topics that are covered in detail in this textbook include cell structure, neural signal transmission, biological membranes, evolution, photosynthesis, immunology, and much more. In this completely revised edition, new topics such as the microanatomy of the cell envelope, voltage homeostasis, and cancer, as well as the echolocation of bats, have been added. The book is aimed at undergraduate and master's students in the natural sciences, as well as doctoral candidates.