“She does have a devoted readership here, but if there’s a problem with her work getting the respect it deserves, it’s probably because it’s historical fiction,” Ms. Miller said in an interview. “Some people who write it are at the top of their game — Mary Renault, Hilary Mantel, Barry Unsworth — but at the same time, it’s full of cheesy, endless series about things like the women of the War of 1812.” The two types are unfortunately lumped together, she said.

Set in 1922, “The Paying Guests” tells the story of Frances, unmarried and dangerously near her late 20s, who lives with her mother in an unwieldy London house suited to a different time. The men are dead. The money has run out. The servants are gone. Frances’s wartime sub rosa affair with another woman is over. Life is a struggle to keep up appearances, fend off creditors, attend to the drudgery of housekeeping and squeeze pleasures from small things. Unable to relinquish the old life she clings to, Frances’s mother refers to the lodgers they are forced to take in — Leonard Barber and his voluptuous wife, Lilian, several notches in class below them — as “paying guests.” But things change, twice. Frances falls into a blissful, ecstatically described affair with Lilian, and the love story begins. Then the book takes a shocking turn, and the crime, or the possible crime (it is never completely clear), comes in.

Ms. Waters did not really set out to be a novelist, nor, in truth, did she know right away she was a lesbian. She grew up in a small town in Wales, where there was minimal acknowledgment of gayness, let alone gayness involving women. “Lesbians just weren’t around,” she said. Ms. Waters had a boyfriend who, she notes, “was a nontraditional bloke as well” — he turned out to be gay, too.

She had a girlfriend — secretly — in college, and then came out in earnest in the late ’80s. She moved to London, found a room in a “lesbian group house,” wrote for lesbian publications and was swept up in an exciting, activist political movement.

Though she still feels lesbianism is a political issue, “The nobility of lesbian life has worn off over time,” Ms. Waters said.

“Given my age and the relative easiness of being gay now in Britain, I no longer read a novel or go to a film just because there are lesbians in it.” She wrote her first book, “Tipping the Velvet,” its title a Victorian slang term for cunnilingus, as an “adventure,” she said, after writing her doctoral thesis on lesbian and gay historical fictions from the late 19th century onward. She was in her 20s, teaching and supplementing her income with the dole, “and I was still young enough to think that ‘this will be a lark, writing a novel,’ ” she said.

Ms. Waters has succeeded in having it both ways, writing mainstream novels that happen to have lesbians in them. “It’s still exciting to me and somehow important to me to be putting lesbians at the center of the story — to be writing historical fiction that is hopefully kind of complicating our sense of the past,” she said.