Kids Book Series is a great website to see what order you need to read a series in!! All you have to do is click on graphic to the left, and then know the first letter of the series name!
by Erin Hunter
Prequel* series Dawn of the Clans (1 - 6 books)
1st series Warriors (1 - 6 books)
2nd series The New Prophecy (1 - 6 books)
3rd series Power of Three (1 - 6 books)
4th series Omen of the Stars (1 - 6 books)
5th series Manga (1 - 6 books)
*Prequel means a story or movie containing events that precede those of an existing work.