In this review, a brief history of the studies on carbocationic polymerizations leading, first, to a better understanding of the mechanisms involved and then more and more to controlled polymerizations, is given and it is discussed why most of the “conventional” polymerization procedures could not be applied to achieve living/controlled polymerizations. Then, the different living systems developed in the 1980–2000 period are described. The application of these new mechanisms for the synthesis of well-defined polymer architectures are reported for the most important types of monomers that can be polymerized by these mechanisms: vinyl ethers, di-substituted olefins and styrenics.