ENThis collective monograph focuses on the development of microtonal music in Eastern and Central Europe from World War I to the present. The authors examine how diverse concepts of microtonality have given way to new composition theories and practices. These scholars hold the view that even between WWI and WWII, microtonal music and its theoretical reflection was the outstanding contribution of Eastern and East-Central European composers to the contemporary discourse of avant-garde music. That provoked radical changes in the composition and performance practice of new music and affected several generations, sustaining and transforming early avant-garde insights. [...] This volume is a testimony to a watershed in research on the history of the microtonal music of East-Central and Eastern European countries. Taken together, the collection presents new research as well as some testimonies on a rich and varied theories and practices of microtonal music in Czechia, Slovenia, Croatia, Serbia, Russia, Lithuania, Latvia, and Austria. A wide-ranging collection of studies is a nice opportunity to share information on microtonality from the involved countries with the international scholarly community. Namely, the contributors explore the interactions of Central/Eastern European and Western music and musicians as creative forces that illuminated cross-cultural exchange. Viewed as a whole, this volume is neither a comprehensive nor an exhaustive account on microtonality within the discussed musical cultures. However, individual contributions as well as the whole volume– and this was exactly what the editors were after–encourage further interest and discussion about history and contemporary musical practices involving microtonality, hopefully not only in Central and Eastern Europe.