The editors have gathered in this book, reviews of past and current studies of mineral groups that have played important roles in geology, environmental science and health science. The various chapters cover the application of TEM and related techniques to: mineral groups in which TEM investigations have been extensive and crucial to the understanding of their mineralogy, namely pyriboles, serpentines, clays, micas and other metamorphic phyllosilicates, oxides and oxyhydroxides, sulfides and carbonates. Some research fields for which TEM is particularly suitable and which have produced significant advances, in particular, are inclusions and traces, extraterrestrial material, deformation processes, non-stoichiometry and superstructures, and biominerals. Nowadays, we are witnessing the push for the improvement of detectors for imaging (direct detection of electrons) and X-rays (silicon drift detectors and annular high solid-angle of collection detectors), the development of new support materials (e.g. graphene) and liquid cells for TEMs. Most of these new technologies have not yet been applied to mineralogical problems but we hope they will be in the near future.