Glycans attached to proteins are known to act as both negative and positive regulators of protein function. Growing appreciation of protein glycosylation's importance has led to increasing amounts of research into understanding how this process works. Chemical biology tools and techniques are bridging the existing gaps in knowledge of the complex nature of glycosylated protein forms. This book describes the development and application of glycoprotein and glycan synthesis technologies as tools for understanding and manipulating protein glycosylation.