How many Project X Alien Adventures books are there?

There are 14 books in the Project X Alien Adventures series by Elen Caldecott, for ages 3-18.

Project X Alien Adventures Books in Order — Wonderlit

Project X Alien Adventures is a 14-book series for ages 3–18 by Elen Caldecott. Each book stands alone — start anywhere.

Start anywhere — each book stands alone.

That said, The Last Stand and Alien Adventures: Orange are great first picks.

No particular order needed — browse and pick what catches your eye.