Will in Scarlet by Matthew Cody

This is the story of Will Shackley and how he came to join Robin Hood, before he was the famous outlaw, and his merry men. Will's father is a nobleman, but Will is forced to grow up quickly when his father fails to return after a crusade. Another nobleman, Sir Guy, accuses Will of murder and then kills Will's uncle and guardian. Will flees but is found by a band of thieves, so he calls himself Will Scarlet to hide his identity. His life is spared when he says he can guide the thieves into the castle to steal treasure, while Will only wants to return to kill Sir Guy. Will, Rob, John, and Much escape the castle, but they're now criminals wanted by the sheriff, Sir Guy, and Gilbert, the leader of the merry men. Will and the others travel the countryside and steal from the wealthy and greedy, so they may help the poor farmers they find. Eventually, their paths must cross with Sir Guy and the sheriff to settle their conflicts.
I really enjoy these kinds of adventures. The young, brave boy is forced to take on adult problems and becomes a hero in the process. They're underdogs against the armies and forces of their opponents. Much's character also has a secret being kept from the others that you know must eventually come out. Will's character changes and grows as he sees the poverty of the farmers and as he spends more time with Rob, John, and Much. The plot contains a good amount of action and adventure to keep readers entertained..