Biophysics is a new way of looking at living matter. It uses quantitative experimental and theoretical methods thereby opening a new window for studying and understanding life processes. This textbook gives compact introductions to the basics of the field (molecular cell biology, statistical physics, etc.) and then provides in-depth discussions of more advanced biophysics subjects going all the way to state-of-the-art experiments and their theoretical interpretations. The book is unique by giving a general introduction to biophysics, yet at the same time by restricting itself to processes that occur inside the cell nucleus and that involve biopolymers (DNA, RNA, and proteins). This allows for a coherent story line that is easy to follow for beginners. At the same time, it allows to achieve more depth, making this book interesting to specialists too.