In modern science the study of materials and their properties has become a major theme of research. Technological developments have provided the tools to design and build optical instruments with nanometer resolution and ultimate sensitivity to visualize materials and study their optical, thermal, and electrical properties. In this course we will describe the most commonly used advanced optical microscopy approaches, including fluorescence microscopy, super-resolution microscopy, near-field and surface-enhanced spectroscopy, and polarization-resolved imaging. We continuously make a link with materials-science research at TU/e (both on nano- and biomaterials) in the lectures.