Ranger's Apprentice series:

The Ruins of Gorlan

The Burning Bridge

The Icebound Land

by John Flanagan

This fantasy adventure series is solid, and I regularly recommend it to kids. It's also up to 12 books, and ain't nobody got time for that!

Will, the 15-year-old protagonist, is drafted by the mysterious Rangers, stealthy warriors trained to fight and, more importantly, to forestall battles through covert operations. Even while training to become a protector of the kingdom, he will face mortal danger.

I don't remember there being any magic in these books, but they share the vaguely medieval setting of many fantasy stories that do feature magic. This series is more about adventure and survival, and of course the perennial middle-school-to-young-adult themes of independence and individualism, while also relying on the support of others and developing mature relationships.

Gripping, entertaining, and relatively quick (for an adult). I'd always meant to read more of them, but I'll probably never get around to it.