NEW YORK—"Fifty Shades of Grey" has joined the 100 million club.

Vintage Books announced Wednesday that sales for E L James' sexually explicit trilogy have reached 100 million copies and have spent 100 weeks on The New York Times' paperback best-seller list. The novels have been translated into 51 languages, including Hebrew, Icelandic and Korean. With a film adaptation planned for 2015, many more sales are likely.

James' books, which originated as fan fiction inspired by Stephenie Meyer's "Twilight" books, immediately topped best-seller lists after Vintage acquired them in 2012. Vintage is an imprint of Penguin Random House.