In this book, Garelli, Mantz and De Battista unify recently proposed control strategies in a generalized framework to deal with different kinds of constraints. The resulting control strategies are based on reference conditioning ideas, implemented by means of supervisory loops which employ discontinuous actions. Although design simplicity is a book priority, the use of well established variable structure systems theory and sliding mode related concepts for theoretical analysis make the book also rigorous and self-contained. The book aims at providing solutions which can be added to pre-existent control designs, and that allow using conventional control tools for the main loop design. Switching signals are always confined to the low-power side of the systems, so that the implementation of the control schemes results extremely easy, both analogously or digitally. The first part of the book (Part I) focuses on providing a description as simple as possible of the methodology to deal with systems constraints in SISO systems. It also illustrates the design and implementation of the developed techniques through several case studies. Part II is devoted to multivariable constrained control problems. Finally, the book presents an extremely simple algorithm for the reduction of the undesired effects caused by manual-automatic or controller switching in multivariable process control.