About 600 books and 66 serials mainly relating to entomology and the natural sciences. The strength is works on British entomology but also includes Europe, North and South America. About one-third were published in the 18th and 19th centuries.

A large number of photographs and negatives taken by Loke Wan Tho on his ornithological expeditions to the Pacific, Asia and Europe in the 1950s and early 1960s, as well as papers, books and maps.