Spiders are wonderful creatures. Their varied and complex range of behavior and highly developed sensory systems are excellently adapted to the environmental conditions - as is proven by their evolutionary success. Over 400 million years, spiders have developed their sensory organs to a fascinating technical perfection and complexity. §In his intriguing book, Professor Friedrich G. Barth puts this technical perfection into the context of "biology", in which the interaction between environment and sensory organs and the selectivity of the senses as a link between environment and behavior play a major role.