Thriller writer Lee Child and The Hunger Games author Suzanne Collins became the fifth and sixth members of the Kindle Million Club after selling over a million books each on the high-tech reader, Amazon.com announced today.

Collins is the first children's author to reach the mark. Her 2008 novel The Hunger Games depicts the struggle for survival of Katniss Everdeen, a 16-year-old girl who takes her sister's place in a to-the-death face-off of preteens and teens that is televised each year in Panem, a dystopian version of the U.S. Of the 24 people who enter the arena, only one survives.

The Hunger Games trilogy concluded with the release of Mockingjay last August. A movie of the first book is due to be released by Lionsgate in March 2012.

Collins, a former children's television writer, first hit it big with Gregor the Overlander, about a New York City boy who discovers giant talking cockroaches, spiders and rats and a hidden society of humans in the Underland. It led to a five-part fantasy series, The Underland Chronicles.

Child has written 16 Jack Reacher thrillers, beginning with Killing Floor, about an Army veteran, Reacher, who wanders into a Georgia town and is quickly arrested for a murder he did not commit. In a review in Entertainment Weekly, Stephen King gave the 1997 novel awards for Best Corrupt Southern Town in a Summer Novel and Best Exploding Warehouse.

Stieg Larsson (The Girl With the Dragon Tattoo) was the first author to sell 1 million books on Kindle, followed by the prolific James Patterson, and Nora Roberts in January. Charlaine Harris (author of the Sookie Stackhouse series, which became True Blood on HBO) joined the club last month.

The Kindle debuted in November 2007 -- and just a few weeks ago, Amazon said that its customers are not buying more books on the device than all print books combined.

Edward B. Colby is the Books section editor of the International Business Times. He can be reached at e.colby@ibtimes.com.