The practical aspects of Lewis acid-assisted stereoselective synthesis, basic principles of Lewis-acid catalysis, stereoisomerism, chemical selectivity and stereoselectivity are the focus of this work. It is aimed at organic-synthetic professionals employing stereoselective Lewis acid catalysts, who wish to increase their understanding and odds of successful outcomes. Intended for researchers, graduate-level or advanced undergrads with a thorough grasp of the fundamentals of synthetic organic chemistry. This is not a textbook thus the reader is freed from pedagogical restrictions. Various areas of Lewis acid catalysis and stereochemistry are selected for recent significant developments. The interplay of structure and reactivity within innovative mechanistic constructs is always involved, and mechanistic models are included when particularly valuable for understanding or predicting observed stereoselectivity. When a detailed mechanistic description is provided, the author has opted not to alter the proposal by the original investigator when no new data requiring its modification is available. The chapters are organized by concepts rather than reaction types.