This set of stamps of the twelve most famous fictional detectives was issued in 1972 to celebrate the 50th Anniversary of Interpol, 1923-1973. When the Sandanistas came to power in 1979 they apparently destroyed all the stamps issued by the Samoza government and printed their own. So, the set is not especially easy to acquire. With the exception of Georges Simenon's Maigret, all the detectives are English speaking. The following paragraphs are translations of inscriptions in Spanish on the back of each stamp on top of the gum.

     The hero of Dorothy L. Sayers first police novel, Whose Body? (1923), was a detective called Lord Peter. Later the well-known personage of Lord Peter Wimsey reappeared in Strong Poison (1930) and in The Nine Tailors (1934). Thin, good-looking, sporting a monocle, Wimsey was the perfect aristocratic detective—elegant and excellent. There was something in his aristocratic nature which led him to try and hide his talents as an investigator, and he was one of the only detectives who found time to marry.

     Along with Dashiell Hammett, Raymond Chandler was the main proponent of the “hard-boiled” school of fictional detectives. His detective hero was Philip Marlowe, who appeared for the first time in The Big Sleep in 1939. In his own words, Chandler tried to create in Marlowe “a man complete and common but exceptional...a man of honor.”

     With the creation of Sam Spade, Dashiell Hammett founded the “hard-boiled” school of detective fiction. Spade’s most famous adventure was The Maltese Falcon (1928), a classic detective novel.
     A Pinkerton ex-detective like his creator, Spade’s approach to crime was direct and honest. In a milieu which mixed violence and treacherous villains, existing outside of normal society, Spade was an intruder who belonged neither to the real world nor that which he was involved in.

     Perry Mason, the defense counsel detective with the incredible success rate was introduced in 1932 with The Case of the Velvet Claws. The novels of Mason are interesting for their detailed attention to legal points, scientific forensic medicine and criminology, a world Gardner himself was familiar with, having practiced law for twenty years.

     This enigmatic and elephantine bloodhound of Rex Stout appeared for the first time in the novel Fer-de-Lance (1934). Since then, Nero Wolfe has continuously impressed readers of detective fiction as one of the unique personages of this genre.
     He is a genius of extraordinary size who detests leaving his home, is dedicated to solving crimes, cultivating award-winning orchids, and drinking beer. In accordance with the popular image of geniuses, Wolfe is presumably of bad character. He is not a hero who understands himself, but always a fascinating one. Wolfe’s stories also contain the presence of one of the agitated “Doctor Watsons” of the detective novel, Archie Goodwin.

     C. Auguste Dupin appeared for the first time in “The Murders in the Rue Morgue”, written by Edgar Allan Poe (1941). With this story Poe created the first fictional detective. “The Purloined Letter” and “The Mystery of Marie Roget” are two other Dupin stories.
     Dupin was an outlandish romantic who inhabited candle-lit quarters in Paris. He was poor but of noble lineage, very experienced, a great smoker who wore green-tinted glasses. He solves his crimes stunningly, using pure analytical reasoning.

     Ellery Queen, who appeared for the first time in "The Roman Hat Mystery," (1929) was invented by two cousins, Frederic Dannay and Manfred Lee.
     Ellery Queen serves as much as investigator as author. He can entertain his reader by relating his own adventures or those of his father, retired Inspector Richard Queen, of the New York Police Department. Like a bloodhound, Queen is a private investigator who works from his apartment on West 87th Street in New York. His stories are famous for their realistic approach to deduction and the full dialogues of the colorful and amusing personages who abound in them.

     A short story collection The Innocence of Father Brown (1911) began the career of one of the most unlikely fictional detectives. Father Brown, the creation of G. K. Chesterton, always used his almost supernatural ability to divine the culprit by pure intuition. Chesterton explained that during the time he served as a rural curate, Brown had obtained an ample knowledge of the forms of human evil, and in this way it was possible for him to use his sixth sense to solve crimes.

     It is said the Earl Derr Biggers was tired of the sinister and evil image of Orientals in detective novels, and in retaliation he created his good and affectionate detective Charlie Chan. Chan debuted in the novel The House without a Key (1925).
     Chan was a Chinese-Hawaiian-American, who approached his cases with a patient Eastern calm and worked to understand the characters of the people he jeopardized. He was distinguished by his quoting of Confucius and his ever-present "Number One Son."

     Maigret has been called by his creator “the mender of destinies.” He is a police officer, but much more, a humanist and philosopher than agent of the law. For Maigret what matters is the criminal and not the crime. In his memoirs, Maigret explains to the reader that he first planned to become a doctor and certainly he resembles more a family doctor than a policeman., His hat, pipe and headquarters in the Quai d’Orfèvres are known by the majority of readers of police stories today. Simenon may well pass into history as the most prolific writer of the 20th century.

     This small Belgian with the egg-shaped head appeared for the first time in Agatha Christie’s The Mysterious Affair at Styles in 1920. Hercules Poirot reached international fame in 1926, when The Murder of Roger Ackroyd was published. The solution of this mystery, of the narrator as prosecutor, originated a violent debate in the world of the mystery novel. The popularity that Poirot received then has continued. His tiny “gray cells” are legendary for their exactitude. Poirot is classified as belonging to the system of intuition, using the theoretical approach instead of the scientific for deduction.

     Arthur Conan Doyle, creator of the most famous fictional detective, introduced Sherlock Holmes for the first time in A Study in Scarlet (1887). Like his predecessor Dupin, Holmes was a personage of reserved character, whose extraordinary powers of reasoning and observation were his elementary means of deduction. Holmes was constantly accompanied by the officious and always faithful Watson who gave the enhancement of caution to his infallible detective. Holmes’ hooked nose, deer-stalker’s cap, meerschaum pipe and violin are some of his unique identifying characteristics.