Amid the growth of the e-book business and online retailers such as Amazon, sales of print books in brick-and-mortar stores have been suffering all year.

Not last week.

Beginning Tuesday, bookstores had a summer savior when fantasy author George R.R. Martin's new book, "A Dance With Dragons," the fifth installment of his "Song of Ice and Fire" series, went on sale.

Independent booksellers nationwide said it quickly emerged as their biggest book of the summer, selling rapidly despite its doorstop appearance (1,016 pages) and hefty price ($35).

It also temporarily upended conventional wisdom in the book business that devoted readers of genre fiction -- whether romance, sci-fi or fantasy -- have begun to prefer reading in e-book format over print. According to first-day sales collected by Random House, more than 170,000 print copies and 110,000 e-book copies sold on Tuesday, the largest opening for a Random House book in 2011.

"What's been really interesting is the physical-digital split," said Scott Shannon, publisher of digital content for Random House Publishing Group. "These days, for a lot of our big titles, digital is outselling physical. That's not what we're seeing here, and it really speaks to George's fan base."

Eager customers waited outside bookstores before the doors opened Tuesday at the Tattered Cover in Denver and Book Culture and Greenlight Bookstore in New York. An event at Barnes & Noble in Burlington, Mass., on Tuesday was attended by 1,600 people. The series has appealed to hard-core fantasy fans, readers of literary fiction and people who have become hooked on the popular HBO series that is based on it, "Game of Thrones," which received 13 Emmy nominations last week.

"It's a wonderful phenomenon," said Cathy Langer, the lead book buyer for the Tattered Cover. "The anticipation has been palpable. People are discovering him now who had never heard of him because of the TV series, so he has all kinds of new readers."

"It's sort of a Harry Potter for everybody," said Paul Ingram, the book buyer at Prairie Lights in Iowa City, Iowa.

Many bookstore owners got a hint of what was to come several months ago, when customers began buying up the first four books, available individually in paperback and in a boxed set. (The first book was published in 1996.) Random House has shipped 4 million copies of the first four books since January.

"It wasn't until a few weeks ago that I realized how big of a deal this was going to be," said Annie Shapiro, an owner of Book Culture. "I can barely keep the back list in stock. For the last few weeks, I was just ordering them in ridiculous quantities."

"A Dance With Dragons" is selling briskly on Amazon, as well, holding the No. 2 spot on the company's books bestseller list on Friday, followed by the boxed set of the first four books.

Fans of Martin have waited more than five years for publication of "A Dance With Dragons," pillorying him online as they wondered if he would ever finish writing. Two more books in the series are expected, although Martin's publisher would not set a timeline for their release.