We are offering you the 4th publication, latest issue, of Musicologica Journal with more attractive graphical design and with a new domain. In this issue we will continue with the research on jazz, rock and the cultural – political events in communist era. More detailed research has been focused on the oldest genre in the area of non-artificial music and jazz with an international research team, Jazz behind Iron Curtain (Rüdiger Ritter, Igor Pietraszewski), therefore it is necessary to confront this research with a situation in rock music. Journalistic contributions describe in detail the ideologists responses in rock music. However, the theoreticians devote their work to this subject only on national research basis (Peter Brhlovic, Daniel Hevier). More extensive confrontational team of researchers was not created in Central Europe. For that matter we are just moving toward the 21st century improvisational music, which is a pendant of the new 20th century music in a new “comprovisation” form (Július Fujak).