Proceedings of the April 1997 seminar. The designation applies to external static magnetic and/or electric fields that are sufficiently intense to cause alterations in atomic or molecular structure and dynamics. Thirty-eight contributions discuss the behavior and properties of atoms in strong static fields, the fundamental aspects and electronic structure of molecules in strong magnetic fields, the dynamics and aspects of chaos in highly excited Rydberg atoms in external fields, matter in the atmosphere of astrophysical objects (white dwarfs, neutron stars), and quantum nanostructures in strong magnetic fields. Contributors hail from such disparate fields as atomic and molecular physics, theoretical chemistry, and astrophysics.