In recent decades, electronic-structure calculations of solid-state materials have become a standard tool in materials science and engineering. The ab initio methods provide a unique insight into materials behaviour at the atomic scale. This length-scale is still rather challenging for a majority of experimental characterization techniques (even those with the highest resolution). The reliability of first-principles methods as well as their applicability of to a wide range of materials made them an excellent theoretical complement to numerous experimental research tools. A prominent example is phenomena related to magnetic and spectroscopic properties of materials. The electronic structure and related characteristics determine a response of materials to not only external fields but also many other characterization probes (light, X-ray, gamma, electrons, …). As a practical complement to theoretical aspects, the course will also provide a hands-on experience with performing the quantum-mechanical calculations using suitable software tools. The students will synergically combine both theoretical and practical knowledge when working on individual projects related to specific materials-science problem.