Sei Sonate per Cembalo by Carl Philipp Emmanuel Bach. Elgar’s copy signed and dated 1869, [he would have been 11 or 12 years old – this is the earliest extant example of Elgar’s full signature] from Elgar’s library. Total of 35 pages, with Sonata IV annotations on pp. 16-17, indicating that Elgar was studying the structure. For C.P.E. Bach's performance history with the Hallé please explore here
archive.halle.co.uk/composer/bach-car...