The Twelve Days of Bookmas -- Day 7 #12daysbooks

Don't forget about the big contest at BookEnds. If you know the answer, click on the link and leave your answer in the comments to win free books. Or just click on the link to show the agents that I'm a power in the blogosphere. Here's today's puzzle, followed by my clue.

When I was an editorial assistant I helped my boss with a number of licensed books, books that were based on television shows or movies. My boss’s job was to hire writers for the projects, obviously edit, and work on the books and obtain all permissions and approvals from the licensee with regard to the books. That meant approval over who was writing the book, approval over the storyline, and approval over the final manuscript (among other things, like covers, advertising, etc.). My job was to spend a lot of time at the fax machine waiting for approvals to come through and sending material that needed approval.

During my five years at Berkley Publishing we published a series of licensed books that were so successful the show actually ended the year I started working at Berkley, but the books went strong for the entire five years I was there and, in fact, continued to be published long after I had started BookEnds. What was this series?

My clue: Spring in the air.