From time to time, not only landscape architects should discover their world they supposed to know. Therefore landscape perception and our access to creative perception of our environment has to be constantly reinvented. Though inventions basically follow an ambivalent tension between uncertainty, known and nonknown, precision and opennes as well as between theory and practice. Where do good ideas come from? How do groundbreaking inventions happen? The symposium "The essence of invention" adresses these questions with renowned speakers. Speakers /// Gert Heidenreich, Writer, journalist, radio announcer /// Prof. Dr. h.c. Bernard Lassus, Landscape architect and theorist /// Prof. Dr. Klaus Mainzer, Philosopher, philosophers of science, TU Munich /// Dipl.-Phys. Dr. Wolfgang Morawek, German Patent and Trademark Office /// Prof. Dr. sc. ETH Zürich Udo Weilacher, Landscape architect, TU Munich