The book deals with polar effects in carbohydrates and how these effects control the stereochemistry of carbohydrate reactions. This is important for understanding the mechanisms of certain carbohydrate reactions, including enzymatic reactions such as glycosidases, a very important group of enzymes in living matter. It is also very useful for synthetic carbohydrate chemists who would like to synthesize stereoselectively certain classes of carbohydrates. This book will be a very important source of information for practicing synthetic carbohydrate chemists. The book will also be helpful for organic chemists, or for those studying glycobiology.