Part 1 Five-membered heterocyclic compounds with two nitrogen atoms in the ring, S.T. Mullins: pyrazole; indazoles; imidazoles; benzimidazoles. Part 2 Five-membered heterocyclic compounds with two different hetero-atoms in the ring, J.D. Hepworth and M. Wainwright: isoxazole and its derivatives; benzisoxazoles; oxazole and its derivatives; benzoxazoles; isothiazole and its derivatives; benzisothiazoles; thiazole and its derivatives; benzothiazoles; isoselenazoles; benzisoselenazoles; isotellurazoles and benzisotellurazoles; selenazoles; benzoselenazoles; benzotellurazoles. Part 3 Five-membered heterocyclic compounds with three hetero-atoms in the ring, D.J. Rowe: 1,2,3-triazoles; triazolines; 1,2,4-triazoles; 1,2,3-oxadiazoles; 1,2,4-oxadiazoles; 1,3,4-oxadiazoles; 1,2,5-oxadiazoles; 1,2,3-thiadiazoles; 1,2,4-thiadiazoles; 1,2,5-thiadiazoles; 1,3,4-thiadiazoles; selenadiazoles; other five-membered rings with three heteroatoms; heterocyclic rearrangements. Part 4 Five-membered heterocyclic compounds with four heteroatoms in the ring, J.H. Little: tetrazoles; oxatriazoles; thiatriazoles; dioxathiazoles and oxathiadiazoles; dithiadiazoles and dioxadiazoles; phosphorus containing heterocycles.