For the second, he decided to go on his own, blogged about the writing experience as he did it, and built a small but devoted following of a few hundred readers.

Then came Wool, a sci-fi adventure about a future world in which humans live in an underground silo, faced with the prospect of certain death from the toxic winds if they ever go outside — until one of them survives.

The 58-page novelette took on a life of its own. Last October, word of mouth caught on and sales picked up. Howey quickly added four more stories to the Wool series. Sales skyrocketed.

This year, Howey found himself selling 50,000 of his stories a month, and he has been earning a six-figure income or close to it every 30 days, though he notes the business has its ups and downs with many lean times before finding success.

Two months ago, director Ridley Scott optioned it for a movie, and Random House is publishing the hardcover edition in the United Kingdom next year.

“We’re in the position where we’re turning down offers here in the States,” he said. “Self-publishing has become a position of power, not a position of last resort.”

His success proves a theory he had about the self-publishing phenomenon even before the success of Wool. “With self-publishing you don’t waste your time trying to get published, which can take years of query letters and agenting, and all this stuff,” said Howey, who will be teaching a three-day workshop Wednesday-Friday on the science fiction novelette during the Miami Book Fair International. “You go straight to the real gatekeepers, which are the readers. If they respond favorably and you have sales, you can leverage that into a writing career. If they don’t, you write the next thing. Either way you’re not spending your time trying to get published, you’re spending your time writing the next work.”

A large part of the shift in the balance of power comes as a result of e-books and the ease of self-publishing.

“Because of the world wide web, we have a distribution system we didn’t have before. Today you can find an audience immediately online,” said Chris Kenneally, the director of author relations at the Copyright Clearance Center, who will be moderating a panel on self-publishing at the Miami Book Fair International

That, he said, has big publishing houses eyeing the trend warily. “What is dramatic about the self-publishing revolution,” he said, “is it kind of levels the playing field.”

Amazon CEO Jeff Bezos saw what was happening long before others took it seriously.

“I predict we will surpass paperback sales sometime in the next nine to 12 months. Sometime after that, we’ll surpass the combination of paperback and hardcover,” he told USA Today.

That was in 2010.

By the time of his quote in July of that year, e-books had already surpassed hardcover sales on the site. For every 100 hard covers sold, Amazon sold 180 digital books.

For all of 2011, BookStats estimated that trade publisher e-book revenues were $1.97 billion, or about 16 percent of the total trade industry . Adult fiction e-book sales more than doubled over the previous year, making up 31 percent of the category’s total.

Sales are still climbing. The January 2012 monthly StatShot reported almost $100 million in adult e-book sales, a 49.4 percent increase over the same period a year earlier. The number of self-published books produced annually in the U.S. has nearly tripled, growing 287 percent since 2006, with 235,625 print and e-titles released in 201, according to a new analysis of data from the research firm Bowker announced in October.