For Lucy Worsley, a lifelong fan of Sir Arthur Conan Doyle’s perpetually perceptive detective Sherlock Holmes, the question that propels her new 3-part PBS series “Lucy Worsley’s Holmes vs. Doyle” was simple.

She wanted to know why Doyle grew to hate his one great, incredibly popular creation. Why, she decided to investigate, did Doyle “kill off” Holmes in a Swiss waterfall – and then years later bring him back alive?

“Doyle was a true professional in that he wrote for the marketplace,” Worsley, 50, explained from London in a virtual interview. “When he struck gold with Sherlock Holmes, he was almost slightly ashamed of having written this commercially successful project.

“It’s been very interesting the last few years, the way the values that we hold have shifted,” she observed. “People previously considered lowbrow are now allowed to be part of the canon of great writers.

“Agatha Christie, for example. Her work was commercially successful and ‘trashy’ — code for ‘by a woman’ in her case, I think.”

Doyle’s displeasure with his detective she traces to – where else! – his childhood.

“Arthur’s uncertainty about his own position in the world is the key. When he was growing up, his mother was clutching onto the bottom of gentility. There wasn’t much money growing up in Edinburgh. There was this whole issue of the absence of his father who was in an asylum for an alcoholic disorder.

“In Victorian terms, these are dark family secrets. Shameful things you don’t want to get out.

“What he wanted to do was to climb out of that and become a great man of letters. As he saw it Sherlock was pulling him down again.”

How then to make her “Homes vs. Doyle” series work?

“With this genius idea of telling the story of Arthur Conan Doyle and Holmes as if they’re two characters involved in this fight to the death. Then, everything fell into place.

“At first, Arthur’s doing well because he decides to kill Sherlock Holmes. Holmes goes over the Reichenbach Falls. That’s the end of him!

“But then, Holmes comes back (with new stories). He’s alive! And actually Sherlock Holmes wins — because he’s still alive today!

“Everybody wants to know about him, he’s still on the TV.  And Arthur Conan Doyle? Not so much.”

As to Holmes’ influence today, “It’s in the oddball detective, isn’t it?

“All detectives, it seems, are oddballs, outsiders, damaged in some way. Their outsider perspective is why detective fiction particularly appeals to nerds and geeks. Because in detective fiction, it’s the nerd and geek who always go to the ball, isn’t it?

“That’s why I like it. It’s my chance to go to the ball.”

“Lucy Worsley’s Holmes vs. Doyle” airs Sundays, Dec. 8-22 on PBS, PBS.org and the PBS App.