Publishers vary by country. In the UK the series was published by Bloomsbury Publishing and in the US Scholastic published the series.
Geronimo Stilton published them
The Guardians of Ga'hoole series was written by Kathryn Lasky and published by Scholastic Inc.
The first book in the series, "The Princess Diaries," was published in 2000. The final novel in the series, "Forever Princess," was published in 2009.
Aladdin Paperbacks, an imprint of Simon & Schuster published the Pendragon series by D. J. MacHale.
2005
The Reptile Room, the second book of the series, was published on the 30th September 1999.
Scholastic Press published the Hunger Games series.
The Jedi Quest novels were published by Scholastic.
Harper Publishing published the "Little House" series.
The Twilight book series was published by atom book publishers.
HarperTeen