It’s not too late.

“Sherlock” is returning to PBS on Sunday for a third season, and for those who haven’t watched it, it is worth starting now, and even catching up with the first two seasons (at PBS.org or Netflix.)

It would be unfair to say that this BBC production is the best Sherlock Holmes ever: There have been so many, and so many great ones. But it is certainly the right one for right now.

There is no easy explanation for why this Arthur Conan Doyle character has such a lasting hold on the public imagination; possibly only Dracula has had as many incarnations. And that may be a clue to the detective’s enduring popularity.

Image Nicol Williamson as Sherlock Holmes in “The Seven-Per-Cent Solution.” Credit... Shout! Factory

Vampires, after all, supposedly symbolize uncontrolled desire and repressed sexuality. It could be that more than almost any other sleuth, Sherlock Holmes represents logic and the unapologetic triumph of reason over emotion. And especially in this age of ambivalence and subjectivity, a purely cerebral hero is particularly welcome.