‘The Days of Anna Madrigal’by Armistead Maupin (270 pgs, Harper, $26.99)

The hills are still firmly in place, the Golden Gate Bridge remains a bright symbol of welcome, but San Francisco has changed radically since Armistead Maupin began charting the interlocking lives of a handful of its colorful fictional denizens in 1976. The city that was once a beacon for people looking to escape the strictures of conformity — and the puritanical streak in American culture — has become a high-amenity bedroom community for the epicenter of the tech universe, Silicon Valley. And so the bohemian aerie at the center of Maupin’s beloved “Tales of the City” novels, 28 Barbary Lane, has passed from the hands of Anna Madrigal, the one-woman marijuana dispensary who presided over her tenants as both a spiritual guru and a surrogate mother.

Now, the building belongs to dot-commers who, in the words of one of the characters from Maupin’s new novel, “The Days of Anna Madrigal,” have “made it look like a five-star B and B.”

Say it ain’t so, Anna! Or rather Mrs. Madrigal, as she was mostly referred to in the early novels in this series, of which this new book is the ninth and — once again, say it ain’t so! — the last.

Time is a one-way street and has changed Anna as it has changed her city. She has had a series of strokes and has had to descend from her own little Olympus. Now in her 90s, she resides in a more easily accessible neighborhood, with a caretaker, the transgendered Jake, to help her light her candles and fire up the vaporizer. For while she still offers joints to visitors as if they were canapés, Anna must employ an elaborate contraption that removes the smoke from the weed, and features a “mouthpiece that looked as if it belonged on a wind instrument of some kind, possibly a bagpipe.” (What’s more: She’s now got a prescription.)

When Maupin began writing the columns in The San Francisco Chronicle that became the first “Tales of the City” novels, they were in a sense radical social manifestos sneakily disguised as popular entertainment. Anna herself was revealed to be transgendered, but by the time this was discovered, she was too lovable to seem strange.

Throughout the first six novels, Maupin described the intimate lives of gay men and women with a breezy charm that never shied away from ripe sexuality, foreshadowing the entry of gay characters into mainstream film and television in the next decade. Michael Tolliver, one of the series’ central characters, gleefully explored the topography of cruising the city almost four decades before “Looking” was a twinkle in an HBO executive’s eye.

Now that the culture has caught up with the books, Maupin’s frank exploration of the lives of Anna and her makeshift family — surrogate sons Michael and Brian Hawkins and daughter Mary Ann Singleton, and the spouses and children they’ve sprouted — doesn’t have the radical bite beneath the chummy veneer. But for those who’ve followed these characters through the decades, the new book provides a necessary valedictory lap: a final toke, if you will, on a literary joint that has provided a light, sweet high for a long time.

Maupin’s adeptness at fluid dialogue, his flair for shaping characters who thread the needle between pop archetypes and singular human beings, and his great gift for intricate if occasionally preposterous plotting are all on display in the new book, which focuses on the later life of the title character.

Unusually, Maupin departs from the contemporary scenes to include chapters set in Anna’s distant youth — back when she was a he, Andy, a shy boy growing up at his mother’s bordello in dusty Winnemucca, Nev., furtively putting polish on his nails.

Harking back to his early cliffhanger style, Maupin creates a mystery surrounding Anna’s sudden desire to return to her hometown, which Andy fled at 16 to head for the big city. The flashback chapters are among the novel’s most atmospheric, evoking the young Andy’s affectionate rapport with the most motherly of his mother’s employees and the dramatic fallout from his crush on a local boy of Basque extraction. Although the secret of Anna’s name was revealed long ago (hint, or memory-jogger: It’s an anagram having to do with her gender switch), it turns out there’s more to the story.

Meanwhile, in the present, most of Anna’s acquaintances are making plans to attend the Burning Man festival in the Black Rock Desert in Nevada. Michael is being semi-willingly inaugurated in the strange rites there by his considerably younger husband, Ben, while Brian’s daughter, Shawna — a bisexual who’s written a hit novel composed entirely of text messages — also plans to attend, and to find a sperm donor for the baby she’s decided to have. Somewhat more incongruously, Mary Ann shows up, as a sort of fancified candy striper assisting at the medical tent.