Kim Edwards' THE MEMORY KEEPER'S DAUGHTER was, in its first incarnation as a hardcover release last year, the embodiment of a modest success. Viking released it with an intial print run of 11,700; total copies in print were around 30,000. As Pamela Dorman, who acquired the book for Viking in 2003 (before jumping ship to Hyperion more recently) put it, the book "was off to a quiet start."

But as the NYT's Motoko Rich reports, since the book came out in paperback in late May, it has been climbing best-seller lists and enjoying rapid sales at places like K-Mart, Barnes & Noble and independent bookstores across the country, inspiring comparisons to previous paperback sensations like THE KITE RUNNER and BEL CANTO - to name but a few.

"That's the kind of book you all love because it means that not only is word of mouth happening, but you know that something mysterious about this book is really seeping into people's hearts and minds," said Susan Petersen Kennedy, president of Penguin Group USA, whose Riverhead imprint published THE KITE RUNNER. And though hardcover sales were slow but study, "[this] told us that in paperback it was going to be a great addition to the category," said Zan Farr, commercial fiction buyer at Borders Group, who noted that customers were recommending the novel to friends.

Edwards' success does speak to how a book can have a second - and certainly more permanent - life as a paperback. With the growing prominence of paperback originals (be they in mass market or trade) it does beg the question of how important hardcovers really are, especially since the target audiences are so different. "I think of paperback readers as the smarter, hipper, younger readers," said Marty Asher, editor in chief of Vintage/Anchor Books, adding that "it just takes a while until people realize what's going on, and word of mouth takes over on a different level."