I. Development of the peripheral nervous system: cell line segregation and chemical differentation of neural crest cells (N.M. Le Douarin and J. Smith). II. Neurotransmitter plasticity in the peripheral nervous system (I.B. Black, J.E. Alder and E.F. La Gamma). III. Neurotransmitter plasticity and its regulation by environmental factors in vitro and in viro (S.C. Landis). IV. The ultrastructure of noradrenergic and cholinergic neurons in the autonomic nervous system (Ph.R. Gordon-Weeks). V. The ultrastructure of peptide-containing neurons (I.M. Varndell and J.M. Polak). VI. Chemical neuroanatomy and the analysis of neuronal circuitry in the enteric nervous system (J.B. Furness, I.K. Llewellyn-Smith, J.C. Bornstein and M. Costa). VII. Peptide hormone-producing endocrine/paracrine cells in the gastroentero-pancreatic region (F. Sundler and R. Hakanson). VIII. Transmitters and peptides in autonomic ganglia (M. Schultzberg and B. Lindh). IX. Autonomic innervation of the cardiovascular system (Chr. Owman). X. Airways, oral cavity and salivary glands: classical transmitters and peptides in sensory and autonomic motor neurons (J.M. Lundberg, C.-R. Martling and T. Hokfelt). XI. Origin, distribution, and functional aspects of aminergic and peptidergic nerves in the male and female reproductive tracts (Chr. Owman and M. Stjernquist). XII. The innervation apparatus of the rodent iris (L. Olson, Chr. Ayer-le Lievre, H. Bjorklund, T. Ebendal, K.-O, Hedlung, T. Hokfelt, T. Melander, A. Seiger and I. Stromberg). XIII. The sensory system (C.J. Dalsgaard). XIV. Transmitter substances in the peripheral nervous system: an overview of the vertebrates (G. Campbell). Subject index.