These lecture notes focus on the synthesis of robust con- trollers for feedback systems, in the presence of unstruc- tured perturbations. It is assumed, as a prerequisites, that the reader is familiar with the basic linear system and au- tomatic control concepts. In part I interpolation theory is used to solve various single-input-single-output (SISO) ro- bust control problems. While the interpolation approach is awkward for multivariable systems, it provides a very natu- ral and simple approach for SISO systems. In particular the interpolation approach requires only elementary knowledge of...