Glycostructures play a pivotal and crucial role in a myriad of organisms and important systems in biology, physiology, medicine, bioengineering and technology. Within recent years tools have been developed to promote the understanding of their highly complex functions and the associated chemistry and chemical biology, however, many facts still remain undiscovered. These days the area is experiencing a “quantum jump”. Therefore the Editors in collaboration with six responsible Section Editors completely revised and updated the 1st edition to give up-to-date information on glycostructures, their chemistry and chemical biology, and present them in the form of a comprehensive and strictly systematic survey. The texts are furnished by more than 2500 figures, chemical structures and reaction schemes (including more than 12,000 individual chemical reactions), and more than 9,000 references. In concept and content this Major Reference Work received an essential improvement and expansion. Whereas chapter 1, 2, 3, 7, 8, and 9 are updated, expanded and rearranged versions of the 1st edition, many new subchapters are included in the chapters on monosaccharides, oligosaccharides and polysaccharides. The importance of the saccharide metabolism as well as the involvement of complex glycostructures in biologically and medically relevant processes are considered by addition of two large totally newly conceived chapters. Further, another novel chapter featuring key technologies and tools for functional glycobiology is incorporated. Responsible for this major update are the Section Editors who solicited a large number of highly reputed new authors to cover the changes in the content and to write the major supplements.