gossip girl book 1-13

There is only 11 books in the Gossip Girl series.
1. Gossip Girl
2. You Know you Love Me
3. All I Want Is Everything
4. Because I’m Worth It
5. I Like It Like That
6. You’re The One That I Want
7. Nobody Does It Better
8. Nothing Can Keep Us Together
9. Only In Your Dreams
10. Would I Lie To You
11. Don’t You Forget About Me

This is the prequel of the Gossip Girl series.
It Had To Be You

There is also 2 spinoffs from the Gossip Girl series.
1. Gossip Girl: The Carlyles
2. Gossip Girl: The Carlyles: You Just Can’t Get Enough

And there is also the It Girl series which follow Jenny Humphrey's life in Waverly Prep boarding school.
1. The It Girl
2. Notorious
3. Reckless
4. Unforgettable
5. Lucky
6. Tempted

Episode 1 of sesason 1 of Gossip Girl is named Pilot.