Defined in the broadest sense, Glycobiology is the study of the structure, biosynthesis, biology, and evolution of saccharides (sugar chains or glycans) that are widely distributed in nature in all living life forms. Glycobiology is now one of the more rapidly growing fields in the natural sciences, with broad relevance to many areas of basic research, biomedicine, and biotechnology. The field includes the chemistry of carbohydrates, the enzymology of glycan formation and degradation, the recognition of glycans by specific proteins, roles of glycans in complex biological systems, and their analysis or manipulation by various techniques. The third edition of this primary textbook in the field continues in the prior tradition, seeking to provide basic overview of Glycobiology, directed towards the advanced undergraduate or the beginning graduate-level student of molecular and cellular biology and biomedicine. While efforts have been made to avoid a major increase in overall length of the text, substantial changes and improvements include the following: broader focus on all lineages of life forms in nature; wider range of topics, ranging from biology and medicine to chemistry and materials science; expanded international editorial board representing a wider range of expertise; wider range of contributing authors with expertise in specific areas; greatly expanded monosaccharide symbol nomenclature for the representation of glycans; and greater attention to informatics, and relevance to exploration of the glycome.