This work focuses on different magnetic resonance (MR) methods and their applications in solids, like semiconductors and nanostructures. Techniques and combinations thereof are explained and used to analyze defects in semiconductors and nanostructures. Presented for the first time are novelties such as single defects MR as well as state-of-art high-frequency pulse methods: EPR, ODMR, ENDOR. An overview of MR methods currently used to study defects, such as electron paramagnetic resonance (EPR), optically detected magnetic resonance (ODMR), electron-nuclear double resonance (ENDOR) is...