NEW YORK – Catching the wave of a public fascination with vampires, HBO’s “True Blood” has steadily increased in stature to become the cable network’s most popular series since “The Sopranos” and “Sex and the City.”

Based on the series of Sookie Stackhouse novels written by Charlaine Harris and starring Anna Paquin, “True Blood” has grown its Sunday night viewership by 66 percent since its September debut. The first season finale airs this Sunday, with a second season already in production.

“True Blood” casually imagines a world where vampires, telepathic women and “shape shifters” – people who can assume the shapes of animals – are a part of everyday life in a small Louisiana town. A steamy romance between Paquin’s waitress and Bill the brooding vampire, portrayed by Stephen Moyer, is the show’s center.

The HBO series also benefits from proximity to today’s much-anticipated release of the “Twilight” movie, another spooky drama about a girl and the vampire who loves her. Another parallel: “Twilight” is also based on a literary series.

Alan Ball, who produced HBO’s “Six Feet Under,” came to the network with the idea of adapting Harris’ novels into escapist entertainment.

“After ‘Six Feet Under,’ where as an artist and a person I got to explore my whole relationship with grief for about five years, I just felt, OK, I don’t really need to spend any more time staring into the abyss,” Ball said.

Ball’s pitch was basically all it took to sell HBO’s executives on the idea, said Michael Lombardo, HBO’s chief of West Coast operations. Ball kept the foreboding darkness expected in vampire stories, spiced up the sex and violence, mixed in humor and explored the theme of outsiders in society, he said.

The novels are centered on Stackhouse, so Ball said he had to develop some of the characters around her to avoid overworking Paquin. Harris is unlikely to mind any artistic licenses; all seven of her Stackhouse novels rank in the top 30 of The New York Times paperback fiction best-sellers list.

The fictional genre of women with supernatural beaus was new to Ball, but he’s been impressed with how the stories keep surprising him and how fresh the world created by Harris seems.

“If I wasn’t making this show,” he said, “I’d be watching it.”