The lack of availability of glycans and glycoconjugates has severely limited the development of the field of glycobiology. This issue of Emerging Topics in Life Sciences features nine reviews by respected scientists in the field and deals with the application of metabolic engineering to the production of these complex carbohydrate or saccharide structures. The cover image illustrates that capsular polysaccharides and other bioengineered compounds can be generated by engineered cells, such as Escherichia coli, through the application of various metabolic engineering tools and strategies. The image was kindly provided by Robert J. Linhardt (Rensselaer Polytechnic Institute) and designed by Asher Williams (Rensselaer Polytechnic Institute).