Abstract: The use in a ribosome display system for selection of a specific binding pair member (e.g. antibody molecule) able to bind a complementary specific binding pair member (e.g. antigen) of encapsidating specific binding member/ribosome complexes in a viral coat, optionally in combination with incorporation of an Midvariant RNA template and optionally one or more other improvements selected from: a glycine-serine tether, protein disulphide isomerase, protein disulphide isomerase in combination with oxidised and reduced glutathione at a ratio of between 1:1 and 10:1, addition of oxidised and reduced glutathione at a ratio of between 1:1 and 10:1 after 30 minutes of in vitro translation; blocking with heparin during selection.