Cornerstone - Nick spalding

The Cornerstone
A great book will transport you to another world... literally, if you're not careful.

On a gloomy Thursday afternoon, Max Bloom enters his local library in a last ditch attempt to stave off an epic case of teenage boredom. Among the hushed stacks he discovers The Cornerstone, an ancient book tucked away on a dusty, forgotten shelf. Opening the cover, Max is instantly transported to an alternate dimension full of things intent on killing him - thus avoiding boredom with remarkable success.
He meets a beautiful girl called Merelie (brilliant), who tells him he could be a Wordsmith, a sorcerer able to craft magic from the written word itself, one strong enough to save both their worlds from the Dwellers - hideous monsters from beyond the universe (not so brilliant).
This all sounds completely unbelievable. The kind of thing you'd read in a fantasy novel. But The Cornerstone doesn't lie... and the danger is very real.
In a world threatened by monsters, where books are worshipped and powerful magic exists, Max Bloom must make a choice: close The Cornerstone and run home - or trust Merelie, become a Wordsmith, and save two worlds from certain destruction...