The last thirty years have witnessed an enormous e?ort in the ?eld of robust control of dynamical systems. The main objective of this book is that of presenting,inauni?edframework,themainresultsappearedintheliterature on this topic, with particular reference to the robust stability problem for linear systems subject to time-varying uncertainties. Thebookmainly focuseson thoseproblems for which ade?nitive solution has been found; indeed most of the results we shall present are given in the form of necessary and su?cient conditions involving the feasibility of Linear Matrix Inequalities based problems. For self-containedness purposes, most of the results provided in the book areproven.Wehavetriedtomaintainthedevelopmentoftheproofsassimple as possible, without sacri?cing the mathematical rigor. Some parts of the book (especially those contained in Chaps. 2, 3 and 5) can be teached in advanced control courses; however this work is mainly devoted to both researchers in the ?eld of systems and control theory and engineers working in industries which want to apply the methodologies p- sentedinthebooktopracticalcontrolproblems.Tothisregard,asthevarious resultsarederived,theyareimmediatelyreinforcedwithrealworldexamples.