Several complex variables. After a quick introduction to complex structures and holomorphic functions of several variables we turn to the special features of higher dimensions: the Hartogs phenomenon, CR-structures, pseudoconvexity and the Lewy extension theorem. We define the \(d\)-barb complex and the Kohn-Rossi cohomology, discussing its connection to interior singularities. The lecture concludes with an introduction to 3-dimensional CR-manifolds.