Premise: Before Green Gables is the title of a prequel to the Anne Shirley series. The book was published in 2008 by Puffin, a division of Penguin Books, as part of Puffin's celebration of Anne Shirley's centennial anniversary, which will also see the Anne Shirley series re-released to commemorate the event. The first book in the Anne Shirley series was "Anne of Green Gables", which was published in 1908.
Hypothesis: The Anne Shirley series was published before Before Green Gables.