When editors at the University of California Press pondered the possible demand for “Autobiography of Mark Twain,” a $35, four-pound, 500,000-word doorstopper of a memoir, they kept their expectations modest with a planned print run of 7,500 copies.

Now it is a smash hit across the country, landing on best-seller lists and going back to press six times, for a total print run  so far  of 275,000. The publisher cannot print copies quickly enough, leaving some bookstores and online retailers stranded without copies just as the holiday shopping season begins.

“It sold right out,” said Kris Kleindienst, an owner of Left Bank Books in St. Louis, which first ordered 50 copies and has a dozen people on a waiting list. “You would think only completists and scholars would want a book like this. But there’s an enduring love affair with Mark Twain, especially around here. Anybody within a stone’s throw of the Mississippi River has a Twain attachment.”

Farther upriver, at the Prairie Lights bookstore in Iowa City, Paul Ingram, the book buyer, said he initially ordered 10 copies, but they disappeared almost immediately.