Fantasy Book, where a normal school kid bumps into a wizard in the woods, and ends up learning about a dragon threat. Read in 2009, first book in a 3 book series which was bound into one book. Second book had the wizard go missing at the starts.

[Alexander]

I do not remember much else about this book other than a chapter where he seems the dragon following a train, and i think its hiding in the mountain. And at some point a kid in school gets controlled and walks out the school and throws himslelf off a high ledge