Neuroanatomy brings crucial information about the structure and functioning of neurons. Chemical communication is nowadays one of the top open subjects for investigations of the plasticity and multifunctionality of neuronal networks. This unique monography presents results of works which led to discovery of new neurons and neuronal network connections in unexpected areas of the visual system in the model organism Drosophila melanogaster. The scientific methods described in this book allow to obtain high resolution data. Author gives a comprehensive review of the best available antibodies, transgenic fly lines and chemical reagents.