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.
The book Green Gables is the prequel to the Anne Shirley series
I think changing the book name, or just omiting the actual part of the book name fooled the system, although that is the name of the book the prequal had the word before in it