Abstract
Our understanding of the way antibodies are built in vivo has provided an approach for engineering synthetic human antibodies in bacteria. Such antibodies have not only been raised against foreign antigens, but also against highly conserved antigens or human self‐antigens, and have considerable practical potential as reagents for research and also as therapeutics. The approach also has implications for the design of antibody repertoires and for engineering other proteins with desirable binding properties. This review takes a personal view.