Last week, tipster Thomas B. alerted us to a change over at Kayo Books, at Post & Leavenworth, saying operations at the 21-year-old bookstore "will shift to on-line and by-appointment sales."

We stopped by the shop, which opened in 1995, to find out more. The store stocks thousands and thousands of vintage, long out of print books, comics and magazines from a variety of genres.

Maria Mendoza, who co-owns Kayo with her husband Ron Blum, told us that by no means does the change spell the end for the shop. To the contrary, she happily shared that she and Blum had signed a new, seven-year lease for the store with a minimal, and affordable, rent increase.

"This store is part of old San Francisco," she said. "You cannot open a store like this at current, market rate rents."

But with the new lease comes a new business model. Mendoza confirmed that the store, which has long been open to walk-ins Thursdays-Saturdays, will soon switch to a by-appointment only. Kayo will, however, continue to sell via mail order through its website. Mendoza said that though she and Blum love their business, they felt it was time for a change.

As we perused the store's vast offerings, Mendoza spoke of the store's customer base. "We appeal to all kinds of people," she said. "We get people who are into the visual arts, or artists who are looking for cheap material for collages. Some people come here because it's an unusual place, like a museum. Then there's people in the neighborhood who are looking for something to read."

The locals, Mendoza tells us, are people who like to read the kinds of books no longer considered commercially viable by publishing houses. The shop carries a staggering variety, including novels based on popular films and TV series from the 1960s and '70s, adult novels from that same period, piles of once popular magazines such as Life and Look (neither of which still publishes) and scores of monster movie and science fiction publications. Some of these items date back 50-70 years.

"We have strange categories like 'ballbusters'—novels about liberated women in the '60s, or 'Catholic guilt,' anything in that category might feature nakedness, 'sinfulness' or priests," said Mendoza.

We asked Mendoza which types of books were her biggest sellers.

"That depends on who's here," she said. "We can always rely on mysteries, LGBT titles, comic books, and science fiction." She noted that westerns were particularly popular with regular customers. "We have around five people who'll come in and buy 100 westerns at a time."

Auctions, estate sales, and fellow collectors are among the sources through which the store is stocked. "We've been specializing in this for quite awhile," she said. "We know people, but it is getting harder to find stuff because of the Internet."

Mendoza and Blum, who live in Glen Park with their son, have had a longstanding love affair with the store's "Tendernob" location.

"It always feels like I'm in San Francisco here," Mendoza said. "There's great public transit. I love the architecture, all the beautiful old buildings so close to one another—it's a great neighborhood."

Mendoza said that sometimes, after work, they'll stop into one of the local cafes or catch a flick at the Landmark Opera Plaza or the AMC Van Ness. They also enjoy visiting with neighborhood resident Erle Korshak. Now in his 90s, Korshak is a former publisher and one of the first people to attend science fiction conventions when they began around 1939. "He's got great stories to tell," Mendoza said.

"San Francisco has changed, but there are still pockets of the old San Francisco with down-to-earth people," she said, naming her landlord as one such person. As for the change to appointment-only, which will go into effect on Nov. 1st, she said "we'll see how it goes." Until then, customers can still drop in from 11am-6pm, Thursday-Saturday. Appointments or online shopping are also currently available.

All merchandise is now available at a discount, which will increase by 10 percent every week until the November changes kick in.

Thanks to tipster Thomas B.