1) Introduction to course will cover all type of retinal cells in a typical mammalian retina and their unique architecture. 2) Fundamentals of retinal cell biology; visual cycle, retinal circuitry as well as signal transmission to receptive fields in brain will be included. 3) A more depth organizational perspective will be given by cross comparing several organisms including human, mouse, octopus, jellyfish, drosophila, sea urchin and further. 4) An evolutionary comparison of retinal cell types and their origin will be covered. 5) Finally, retinal development and its gene regulatory networks will be studied. Specific attention will be given to the transcription factors including Math5, Pou4f1, Pou4f2, NeuroD1 and especially Pax6 which can form ectopic eyes solely by its overexpression in flies.