The last several dozen years have been marked in Polish music studies by a tendency to explore previously uncharted territories in the history of our musical culture, to present and study data concerning forgotten artists and their outputs. Scholars are frequently additionally inspired to undertake such research by round anniversaries of the composer’s or performer’s birth and death. Such dates typically occasion various initiatives related to the given artist’s promotion or in-depth studies of his or her legacy. This has also been the case with the present publication, dedicated to the person and oeuvre of Paul Klecki (1900–1973), an eminent and world-famous conductor who was also a notable music composer. The fiftieth anniversary of his death, celebrated in 2023, has created opportunities for various performance projects such as recordings, concerts, and exhibitions. Most of all, it has provoked a group of scholars to do research in this field. Some of the authors had already previously been preoccupied with Klecki’s life and work. Others expressed their willingness to take up this subject in the context of the approaching anniversary. Initiated by Łódź-based music theorists associated with the Department of Theory of Music at the Grażyna and Kiejstut Bacewicz University of Music in Łódź, the project was joined by theorists, musicologists, historians, and conductors from other academic centres in Poland (the Karol Szymanowski Academy of Music in Katowice, the Krzysztof Penderecki Academy of Music in Cracow) as well as abroad (the University of North Texas – College of Music, the Swiss National Library – RISM Digital Center). The thus formed team, which consists of more than a dozen persons, is responsible for the present publication, which undoubtedly fills many gaps in our knowledge about that intriguing man and artist. It is also the first such extensive and multidimensional study of various aspects of Klecki’s biography and of his work as a conductor and composer.