(b Lüdenscheid, Westphalia, 1817; d Graz, 1882). Ger. composer and musicologist. Settled in Vienna 1846, became friend of Brahms, and wrote some minor works, but is known for his valuable research into Beethoven's sketchbooks embodied in three books, pubd. 1872 and 1887 (posth.). Also pubd. thematic catalogues of works of Beethoven (1868) and Schubert (1874). One of first authorities in textual criticism.
From The Concise Oxford Dictionary of Music in Oxford Reference.