‘From now on, I will accept only Karel Goeyvaerts as my teacher in composition’ exclaimed the young Karlheinz Stockhausen during the famous New Music Summer Courses at Darmstadt in 1951. Goeyvaerts had just explained the very principles of serial organization for which Stockhausen had been searching for some time. In the following years Goeyvaerts 1923–1993) developed those basic principles into variety of composition techniques, and into a stylistic diversity not often encountered in serious music. After having applied serialism to tapegenerated music in the early 1950s and to experimental and aleatoric procedures in the 1960s, Goeyvaerts developed the repetitive element, already couched in some of his serial works, during the 70s and 80s. In his last period, the Belgian composer did not eschew a return to tonality, without however foresaking the core of serial thinking of which he had been the founding father. For many of these tendencies Goeyvaerts was the forerunner; to others he added valuable contributions. Therefore, his artistic legacy should be evaluated against the work of other European avantgarde composers such as Stockhausen or Boulez, or put into perspective by comparing it with the work of his American colleagues such as Babbitt, Carter, Riley or Glass.