Recent advances in spin-sensitive spectroscopie techniques combined with the rapidly expanding capabilities to synthesize novel materials utilizing molecular beam epitaxy (MBE) are stimulating new interest in magnetism and magnetic materials. Epitaxial growth offers opportunities to stabilize and study crystal phases of elemental magnetic materials which do not naturally occur in nature, and to vary the crystal parameters and composition of epitaxial films in precisely controlled ways. Multilayer superlattice films can also be fabricated using MBE. These structures offer unprecedented new opportunities to explore the relationship between crystal structure and various magnetic properties such as spontaneous magnetization, the Curie temperature and magnetic anisotropy in well characterized systems. The present paper reviews some of the more recent work on thin film magnetic systems including structure analysis of film quality, new techniques for probing the electronic and magnetic properties of the films and the important role large scale numerical calculations are beginning to play in guiding the choice of magnetic systems for study.