It's the biggest mystery the master sleuth himself will never get to solve: Why is Sherlock Holmes so hot right now? Of course, the pipe-smoking master-detective has long been revered by Arthur Conan Doyle aficionados who have picked over some 60 adventures featuring the character. But 159 years after Sherlock first appeared in print (his birthday was Sunday), movie producers, television executives, and new fans are flocking with renewed fervor to the classic crime-solver.

First we had Robert Downey Jr.'s showy blockbuster and its sequel. Then Benedict Cumberbatch turned up his collar for an altogether more sardonic affair in a modern BBC adaptation. Then Jonny Lee Miller’s Elementary dared to cast a woman, Lucy Liu, in the role of Watson — ensuring enough exposure to secure a second season on CBS and a coveted post-Super Bowl spot next month. The latest incarnation? A digital comic titled Watson and Holmes, in which the duo is black and lives in Harlem.

So... what gives?

"Every generation or so some kind of cycle happens, some big book or movie begins to start the process and then others seem to follow up," explains Scott Monty, a member of the Sherlock Holmes enthusiast group the Baker Street Irregulars. "Sometimes there are authors and filmmakers who have been working on the idea at the same time. It may be bit of momentum that causes it or a happy coincidence, but we'll take anything."

Conan Doyle was prodigious, and the scores of Sherlock stories he pumped out helps satisfy the desire of modern-day storytellers who want to re-boot the series. Plus, unlike in crime procedurals like CSI or heart-pumping terror dramas like 24, uncanny intuition is Sherlock’s main tool. In our ever-modern, tech-centric world, it's reassuring that someone without gizmos can still come to the rescue with little more than his gray matter.

"He is using his brain more than anything else. That has such appeal, because you could be him," says Monty.

Another factor in Sherlock's renewed popularity? He's a rebel, and Americans love a rebel.

"Partly it's his bohemian, independent nature, his willingness to step outside the rules," says Les Klinger, an expert who has published several books on Holmes. "Partly, it's his 'superhuman' qualities, the ability to focus and devote himself to his mission and to apply reason to matters in ways that others can’t. I think we’d all like to believe that we can 'think' our way out of problems."