[1] Hambreaus studied organ with Alf Linder and musicology with Carl-Allan Moberg, earning his doctorate in 1956 on a thesis about medieval musical notation.
In 1972 he became professor of composition at McGill University, Montreal and he remained in Canada until his death in 2000.
Among his notable pupils are composer Peter Allen and pianist Richard Hunt.
Hambraeus wrote music for a large number of instruments, but he is perhaps best known for his organ works.
Together with Mauricio Kagel and György Ligeti he was among the first to use high modernist compositional methods to compose organ music.