Although Sherlock Holmes is certainly the most well-known fictional
detective, detective or mystery fiction has produced many other
personages have appeared on stamps. Some are the fictional detectives
themselves, some are authors, and some are people involved in motion
pictures based on detective fiction. I have separated this topic into
several sub-topics so the pages will load faster.
an excellent web-site on detective fiction on stamps. It is:
Jeff Dugdale, "Sleuth," JAPOS Bulletin,
Whole Nos. 109:2-4 and 110:3-5.