A spokeswoman for Ms. Atwood declined to comment except to point out that the writer was in Europe this weekend. Mr. Martin could not be reached. Mr. Armstrong died in 2012.

Whether or not fear of Amazon is legitimate, it exists.

When Authors United, a group of writers, reprinted the open letter denouncing Amazon’s tactics in the Hachette dispute as an advertisement in The New York Times, 17 writers and a trust split the bill. Douglas Preston, the founder of the group, said the writers willing to be identified were Mr. Patterson, David Baldacci, Lee Child, Nelson DeMille, Amanda Foreman, Stephen King, Nora Roberts, Stacy Schiff and Scott Turow. Mr. Preston also paid a share, as did the Ansel Adams Publishing Rights Trust.

Seven other contributors asked to remain anonymous. “They were quite specifically worried about the possibility that Amazon would single them out for punishment,” Mr. Preston said.

An Amazon spokesman did not respond to questions on the subject of fear.

Campfire this year is being held under the conditions of utmost secrecy, as usual. Mr. Bezos has rented the entire Bishop’s Lodge Ranch Resort and Spa, which is set on 450 acres a little north of Santa Fe. If you call the front desk seeking a particular guest, the operator will not ring the room or even take a message. There are guards at the front gate to prevent the curious from getting too far.

Mr. Bezos, who built Amazon from its dot-com roots as a bookseller into one of the country’s biggest retailers, knows the psychology of writers, several past attendees said in interviews. “You come to this exclusive event, you are treated fabulously and you get access to the next Steve Jobs, who happens to control how many books you sell,” one said.

Employees at Amazon’s headquarters in Seattle have to pay for their perks, down to the treats from vending machines. And the company is famously tough on its suppliers; the Hachette conflict is just one example. At Campfire, however, there is no stinting.

There are impressive dinners, accompanied by live music. There is horseback riding, skeet shooting and lazing by the pool. In the mornings, there are formal talks on highbrow topics. One guest fondly recalled that the swag included down vests, fleeces, shoulder bags and small suitcases to carry all the loot home. Getting back to mundane reality was postponed for the attendees who took one of the private jets. (Others say they took scheduled flights.)