The 9th International Symposium on High Energy Spin Physics, held in Bonn, 6-15 September 1990, attracted 280 participants from 16 countries. This meet ing covered not only fundamental experimental and theoretical spin phenomena but also technological developments in polarized beams and targets. For the first time intermediate energy spin physics with electron machines was discussed extensively. Highlights included the work on polarized high energy electron beams at LEP and TRISTAN and the failure of the standard model in connection with spin phenomena, in particular the growth of the spin...