Over the past decade, several biological display technologies have emerged for generating large, diverse libraries of molecules through rounds of mutation and selection that mimic the process of natural evolution. Display libraries consist of modularly coded molecules, each of which contains a displayed entity of interest, a common linker, and a corresponding identifying code. They have transformed our ability to rapidly identify proteins, and in particular antibodies/antibody fragments, that bind to orphan targets of interest, and have subsequently found application in basic research and drug/agrochemical discovery. On page 1251, Min Li summarizes the concepts unifying the various display approaches and the types of coding formats/applications described to date, in the context of the technology's suitability for adaptation to studies of protein–protein/target interactions on a global (proteomic) scale.