<P>Introduction.- The enteric nervous system (ENS).- Ganglionated enteric plexuses.- Non-ganglionated enteric plexuses.- Morphological classifications of enteric neurons.- Material and Methods.- Immunohistochemistry.- Immunocytochemistry.- Double labelling post mortem tracing.-Image aquisition of immunofluorescent specimens, counts, morphometry.- Three-dimensional(D-) reconstructions.- Chemical coding of Stach’s neuron types in the pig.- Preliminary note: Cholinergic and nitrergic neurons.- Type I neurons .- Type II neurons.- Type III neurons .- Type IV neurons .- Type V neurons .- Type VI neurons.- Type VII neurons.- Dendritic type II neurons, mini neurons, giant neurons.- Morphological neuron types and their chemical coding in the human.- Nomenclature used for human enteric neurons.- Type II neurons.- Stubby (type I) neurons.- Spiny (type I) neurons.- Type V neurons.- Type III neurons.- Dendritic type II neurons.- Spiny neurons with main dendrites or human type VII neurons?.- Discussion.- What does NF-immunohistochemistry achieve?.- General remarks on equivalent neurons of different species.- Putative functional categories of human enteric neurons.- Plasticity.- Summary.- Acknowledgements.- References.- Subject Index</P>