The birthday of a fictional character does not often set off an international celebration, unless the character happens to be the beloved detective Sherlock Holmes. British writer Sir Arthur Conan Doyle wrote the Holmes mysteries as if they were true stories. Fans have embraced that idea, and this year they are observing the 150th anniversary of the birth of Sherlock Holmes. In the United States, that milestone has inspired film festivals, black-tie dinners and a recent symposium at the Smithsonian Institution in Washington, D.C.


Sherlock Holmes has been recreated in countless forms around the world -- from cartoons to advertisements to movies - even as the stories themselves continue to be published and read. "We're talking about a novel that was first published 117 years ago that still goes strong in its sales," says Holmes scholar Leslie Klinger. "The books have now been translated into over 80 languages, and there are still very large fan bases all over the world."


Those fans are an unusually passionate group. Washingtonian Peter Blau is secretary of the Baker Street Irregulars, a group that takes its name from the street urchins who helped Holmes and Watson solve their cases. Mr. Blau says a favorite pastime of so-called Sherlockians is to play what has come to be known as "the game" -- debating unresolved riddles and inconsistencies in the stories. "Why does Doctor John H. Watson's wife call him James in one of the stories?" asks Mr. Blau. "That is a game that is fun to play, trying to explain some of these things that often have no rational explanation."


Holmes scholar and California attorney Leslie Klinger delves into many of the controversies in his two-volume edition, The New Annotated Sherlock Holmes. The books contain all 56 Holmes stories, together with extensive historical and literary commentary. Mr. Klinger believes the personality of Sherlock Holmes helps to explain his lasting appeal. "We have this fascinating man who knows everything, is always in command, and never seems to have a doubt about what's the right thing to do, even though it may be contrary to law or culture," says Mr. Klinger. "We have Dr. Watson, an intelligent, loyal, dependable friend, and then there's the fascination with the Victorian age."


The character of Sherlock Holmes apparently dates back to Arthur Conan Doyle's youthful days at medical school, where he met a certain professor. "Joseph Bell had a trick of being able to tell, when a patient came in for surgery, a great deal about their complaint - based on things like calluses on their thumbs or a particular style of mud caked to the instep of their shoes," says Daniel Stashower, author of Teller of Tales: The Life of Arthur Conan Doyle. "A few years later when Conan Doyle was casting about for a character to use in this mystery story he imagined, those qualities pressed themselves to the front of Doyle's mind."


The American writer Edgar Allan Poe had already given world literature a detective hero in his character, Monsieur DuPin. But Peter Blau believes it was Conan Doyle who created the model that would spawn so many imitators. "When the first Sherlock Holmes short story was published," says Mr. Blau, "there was no such thing as a detective story. That phrase did not exist. This is something Conan Doyle did that was new. After Conan Doyle killed off Sherlock Holmes, a lot of people started writing their own detective stories."


Techniques pioneered by Conan Doyle continued to show up in those later stories - for instance, the tireless detective and the loyal assistant. Leslie Klinger also singles out some plot devices that, by modern standards, might seem clichéd. "'The butler did it,' in one of the stories, for example," he says. "In another, a man has his head nearly blown off by a shotgun. Surprise, surprise, it turns out the person who has been killed is not the person we think it is. But Doyle was inventing these ideas."


Leslie Klinger says Conan Doyle's creation has kept up with the times. He believes Sherlock Holmes would fit in well with the forensic scientists now seen on popular drama programs on American television like the three CSI series set in Miami, New York and Las Vegas. "I think Holmes would quickly become CSI Baker Street, that he would adapt to a lot of new research tools," says Mr. Klinger, who also sees some differences. "Clearly there is violence in the stories, horrible murders, mutilations, all kinds of ghastly things that happen," he says. "They are not described in the detail we're now used to. I think people enjoy the stories in part because of that, because it is refreshing to go back to a somewhat simpler era."


And while Sherlock Holmes has been attacked in recent years for voicing what seem like prejudiced ideas about women and minorities, Daniel Stashower points out that the stories were also ahead of their time. "The example that always springs to mind," says the Holmes biographer, "is that, in A Study in Scarlet, the first Sherlock Holmes story, Holmes is out-reasoned?defeated?by a woman." Daniel Stashower says that was a remarkable plot twist for the era, and another example of why Sherlock Holmes remains timely a century and a half after his birth.