Notable participants included the Amadeus Quartet, Nadia Boulanger, Paul Hindemith, Igor Stravinsky, Boris Blacher and George Enescu.
[6] During his tenure, Glock arranged performances and commissions of works by many contemporary composers, such as Arnold, Berio, Harrison Birtwistle, Boulez, Carter, Dallapiccola, Peter Maxwell Davies, Gerhard, Henze, Ligeti, Lutosławski, Lutyens, Maw, Messiaen, Nono, Stockhausen, and Tippett.
In Proms programmes Glock expanded as well the presence of Early Music by composers such as Purcell, Cavalli, Monteverdi, Byrd, Palestrina, Dufay, Dunstaple and Machaut, as well as less-often performed works of Bach and Haydn.
Petroc Trelawny noted, "Rumour has long had it that he held a 'blacklist' of banned composers; musicians who didn't fit his ideals.
[11] In 1997 when invited by The Sunday Times to contribute to the partwork 1000 Makers of Music, Glock chose to write appraisals of his mentor and his protégé.
Aged 22, Glock had been a pupil of the first, Artur Schnabel, who maintained that "the years 1919–24 were his most stimulating when composing and the search for a new individual language filled his thoughts".
Glock wrote: “Remarkable is his compulsion to rewrite so many of his works, to make them richer and more striking... [However] during the past 20 years a second Boulez has adopted a more sensual language, yet without a moment's retreat from ceaseless invention.