hilip Arnold Heseltine (30 October 1894 – 17 December 1930), known by the pseudonym Peter Warlock, was a British composer and music critic. The Warlock name, which reflects Heseltine's interest in occult practices, was used for all his published musical works. He is best known as a composer of songs and other vocal music; he also achieved notoriety in his lifetime through his unconventional and often scandalous lifestyle.