Book excerpt: Lewis acids provide inexpensive access to elaborated molecules obtained with high selectivities (regio-, stereo-, and enantioselectivity). Lewis Acids and Selectivity in Organic Synthesis is the first book to deal with these new and promising roles of Lewis acids. The book begins with general considerations on Lewis acids and a description of Lewis acid-carbonyl complexes, which are involved in most of the reactions described: ene reactions, allylsilane and allyltin addition to carbonyl compounds, addition of nucleophiles to acetals, conjugated addition of allylsilanes and allyltins to unsaturated carbonyl compounds (Sakurai reaction), and Diels-Alder reaction. Subsequent chapters examine these issue in detail, with special attention given to the way Lewis acids induce diastereo- and enantioselectivity. The extensive use of schemes (approximately 1000) ensures rapid visual uptake of the information. Lewis Acids and Selectivity in Organic Synthesis serves as a valuable source of information for all who face the challenge of selectivity in organic synthesis.