He is best known for his two-volume work A Practical Handbook of British Beetles, first published by H. F. & G. Witherby in January 1932, a publication which remained the standard work on the identification of British beetles into the 21st century.
He also wrote two other titles: How to Know British Birds, published by Witherby in 1936 and British Beetles, their Homes and Habits.
He described a number of beetles as new to science. In chronological order these were:
In addition to his work on Coleoptera, Joy also discovered the Brown AntLasius brunneus (then unknown in Britain) at Theale in Berkshire on 21 January1923 (Donisthorpe 1927). The Berkshire Birds website credits him as discovering the ornithological potential of Reading Sewage Farm[1].