The 20th anniversary RAGtime workshop took place at the Silesian University in Opava, Czech Republic on October 15-19, 2018. The scientific focus of the workshop was traditionally devoted mainly to problems of relativistic physics of black holes and neutron or quark stars. Large attention was given to confronting theoretical models with up-to-date observations available through both electromagnetic and gravitational wave window to the Universe. Current issues in accretion theory was explored. Participants furthermore attempted to address problems related to cosmology, mathematical aspects of the theory of relativity, and alternative theories of gravity. Last but not least, special attention was putted on national and international collaboration regarding the present and future cosmic X-ray missions. The workshop included a special public lecture 'How to search for Alien Civilizations in the Galaxy?' given by professor Marek Abramowicz on Tuesday, October 16, 2018.