Dr. Robert H. van Gulik (1910-1967) was an accomplished scholar, detective novel writer, linguist and diplomat. During his long tenure in Asia, with the help of his diplomatic status, he was able to form a private collection which excelled in both quality and quantity. When the collection was acquired by the Sinological Institute of the University of Leiden in 1977, it comprised more than 2,500 titles accounting for almost 10,000 volumes, all of these dealing with traditional sinology. Among them were many books on fine arts, classical music and literatuare as well as rare folk novels. This last category included the primary source materials on which his scholarly work, Sexual Life in Ancient China, was based.