This book was written by a group of authors and provides a systematic dis- cussion of questions related to bremsstrahlung in many-particle systems. A number of new results have recently been obtained in this area which require a fundamental revision of the previously existing traditional concepts of bremsstrahlung. This ap- plies both to complicated atoms containing a large number of electrons and to the additional bremsstrahlung in a system of many particles forming a medium. In fact, the traditional approach was rigorously applicable only either to isolated "structureless" particles (e. g.,...