Sensory Transduction in Aneural Organisms. - to Optical Stimuli: Physical Properties of the Light Beam. - Photomotile Responses in Flagellates. - Photomotile Responses in Gliding Organisms and Bacteria. - Phototropism of Lower Plants. - Experimental Determination and Measurement of Photoresponses. - The Photoreceptive Apparatus of Flagellated Algal Cells: Comparative Morphology and Some Hypotheses on Functioning. - Localization and Orientation of Photoreceptor Pigments. - Identification and Spectroscopic Characterization of Photoreceptor Pigments. - Primary Photophysical and Photochemical Reactions: Theoretical Background and General Introduction. - Molecular Aspects of Photoreceptor Function: Carotenoids and Rhodopsins. - Molecular Aspects of Photoreceptor Function: Phytochrome. - Molecular Aspects of Photoreceptor Function in Stentor Coeruleus. - Possible Photoregulation by Flavoproteins. - Bluelight Reception and Flavin Photochemistry. - Basic Concepts in Bioenergetics. - Properties of the Photosynthetic Membrane. - Comparative Discussion of Photoreception in Lower and Higher Organisms. Structural and Functional Aspects. - Photosensory Transduction Chains in Eucaryotes. - Photosensory Transduction Chain in Procaryotes. - Sensory Transduction in Phototropism: Genetic and Physiological Analysis in Phycomyces. - Panel Discussion Sensory Transduction and Photobehaviors: Final Considerations and Emerging Themes. - Participants. Language: English