Imagine if the Rangers from "Lord of the Rings" took apprentices -- what kind of life would that be? 
 John Flanagan does a decent job answering the question in the first book of the Ranger's Apprentice series, "The Ruins of Gorlan." Besides setting up the medieval Anglo backdrop, Flanagan also spins up a solid fantasy story with plenty of monsters, weapons, a likable pair of teenage heroes, and a growing menace from a rarely-seen villain making a comeback. 
 On Choosing Day, Will hopes to be selected for Battleschool -- but he's rejected by all the people taking apprentices. The one exception is Halt, a Ranger. 
 And after Will inadvertently passes a test (climbing up a sheer wall into the Baron's study), Halt accepts him as an apprentice. At first, Will's new life seems to be all chores and unglamorous lessons, but he starts to realize the importance of the Ranger's skills. And at the same time, his fellow orphan Horace is being tormented at Battleschool by a gang of bullies. 
 Unfortunately, the kingdom is in new trouble -- the evil baron Morgarath is starting to send his monstrous Wurgals out once more, and there are even rumors that the ghastly Kalkara are also abroad. When it seems that the king himself may be Morgarath's target, Will and Halt are sent on a mission to stop the Kalkara -- except that the target isn't who they expect. 
 The world John Flanagan conjures up here is pretty recognizably a medieval England-that-never-was, with hints of similarly semi-familiar lands to explore (Gallica, Temujai). And he makes it more his own with elaborate fictional history, slightly too-Tolkienian flourishes (a villain named Morgarath?) and the first blossoming of a solid action/fantasy series. 
 The first half of "The Ruins of Gorlan" is a fairly slow experience, mostly made up of Will and Horace finding out what their new lives are all about. Lots of knife study, ponies, stew and tracking exercises, as well as a fairly nasty boar-hunt. And Flanagan liberally strews the story with plenty of historical backstory, and interesting details about medieval stuff (boar-spears, throwing knives, etc). 
 But about halfway through, the story suddenly becomes much darker, faster and bloodier. While the mild humour is still there ("Halt, Halt!"), Flanagan's tale becomes a deadly game of cat-and-mouse with a pair of assassin Sasquatches. And he definitely knows how to weave a sense of tension and foreboding around the clash between Kalkara and Rangers. 
 Will is also an excellent hero in the Lloyd Alexander mold -- he dreams of being a great knight, but doesn't seem to have much chance of it. And as he works with Halt, he gradually comes to realize that there are ways of serving that are just as important, though not as glorious. And Halt is a good foil for Will -- quirky, taciturn and incredibly tough and deadly. 
 "The Ruins of Gorlan" is an excellent start to a solid fantasy series, and serves as a pretty entertaining fantasy/adventure in its own right. An excellent story for all ages.