D-Branes for Gauge Theories

D-branes are a very efficient tool to engineer gauge theories and study their properties. They have been instrumental in understanding the non-perturbative behavior of gauge theories, in studying their moduli space, and in uncovering new dualities. We give a pedagogical overview of some aspects of the brane constructions focusing on simple examples of theories with eight supercharges in three and four dimensions. Among other things, we discuss configurations based on brane within branes, orbifolds, branes ending on branes, and the Hanany-Witten construction. We discuss how the moduli space of instantons and monopoles are realized in terms of branes. We present various applications, including mirror symmetry in three dimensions, the Seiberg-Witten curve of four-dimensional theories, and an introduction to theories of class S.