Dr. Ángel Martín Pendás is a permanent professor at the University of Oviedo. His research focuses on methodological developments in theoretical chemistry, starting from the introduction of local methods for the treatment of crystalline solids during his doctoral years to fundamental aspects in the theory of chemical bonding in real space. His research group in Oviedo is considered as one of the pillars in the development of new ideas in quantum chemical topology (QCT). Prof. Pendás is an author of more than 150 papers and book chapters.Dr. Julia Contreras-García is based at the Sorbonne University. Her research is focused on the understanding of electronic structure, and its interplay with the energy and properties of the system. Besides this she works on the development, implementation and application of topological tools to analyze the chemical bond in real space, as opposed to Hilbert space - very common in molecules, or reciprocal space, very common in solids. Dr. Contreras-Garcia is an editorial board member of the journal Computational and Theoretical Chemistry and has authored more than 100 publications.

• Introduction.- Topological spaces.- Part I Descriptors.- The electron density.- Electron pairing descriptors.- Weak interactions.- Part II Applications.- Molecules.- Solid state.- Part III Exercises.- Algorithms & software.- Exercises.- Solutions.