ATOMIC PHYSICS 4 extends the series of books containing the invited papers presented at each "International Conference on Atomic Physics." FICAP, the fourth conference of this type since its foun dation in 1968, was held at the University of Heidelberg. The goal of these conferences, to cover the field of atomic physics with all its different branches, to review the present status of research, to revive the fundamental basis of atomic physics and to emphasize future developments of this field as well as its applications was met by more than thirty invited speakers, leaders in the field of atomic physics. Their talks were supplemented by more than two hundred contributed papers contained in the FICAP Book of Abstracts. This volume begins with papers given in honour and memory of E. U. Condon, to whom this conference was dedicated. It continues with articles on fundamental interactions in atoms and Quantum electrodynamics, on the fast progressing field of high energy heavy ion collisions and Quasi-molecules, on electronic and atomic collisions and the structure of electronic and ~-mesic atoms. The volume closes with contributions concerning the application of la sers in atomic physics, a new field of vastly increasing importance to fundamental experiments as well as applications. We feel that this book contains a very stimulating account of the present main streams of research in atomic physics and its possible future di rections.