This book provides an actual overview of structure, function, and application of carbohydrate-modifying biocatalysts. Unlike amino acids and nucleic acids, carbohydrates have been disregarded for a long time by the scientific community, mainly due to their complex structure and a lack of suited experimental methods for structure determination. Meanwhile, the situation changed with increasing knowledge about carbohydrates, glycoconjugates, and carbohydrate-modifying enzymes together with the key roles they play in biological processes such as recognition, signal transduction, and immune responses. An outcome of research activities in glycoscience, which, at the same time, is of great general interest, is the development of several new pharmaceuticals against serious diseases such as malaria, cancer, and various storage diseases.