Fundamentals and applications of the magnetic imaging methods using electron waves will be presented. The first part of the lecture explains the methods of electron holography and Lorentz microscopy, both of which are useful tools for studies of magnetic microstructures. The other part is of applications of these electron microscopy techniques. I will mainly talk about determination of magnetic flux density in a nanometer-scale interface region (i.e., antiophase boundary) observed in Heusler alloys. In addition, I will briefly mention about other topics, nucleation and growth process of the ferromagnetic phase in a perovskite-type manganite, and estimation of magnetic parameters (e.g., magnetocrystalline anisotropy constant) using electron microscopy observations.