The collection contains papers relating to all work undertaken by Colin Matthews as a result of his input into the 1976 publication of the Mahler Tenth Symphony (specifically, revised scores on movements II and III marked up for the copyist) and from his work on the posthumous Cooke publications 'Vindications', 'Gustav Mahler', and 'I Saw the World End'.

Contents include photocopies of many Cooke pieces (lecture scripts, talks, programme notes, sleeve notes, articles, etc.) considered for inclusion in the posthumous publications; some annotated by Berthold Goldschmidt, Bryan Magee, and Hazel Hyde (then Smalley), correspondence, and music scores.