My kids picked this one out for me, because I love Robin Hood. My six-year-old then stole it and made my wife read it to her after I started it. She absolutely loved it and I agree with her.
We meet Charlie who is new at school and is struggling to make friends. A raven follows her and keep pestering her until she goes into the school library. Here she discovers a doorway into another world. Where she becomes an outlaw and a hero.
The baddie is a true scenery chewing baddie. The characters are archetypes. The adventure is iconic. Everything is very telegraphed if you are an adult, but was a surprise for my daughter.
The story is a good stepping stone between early chapter books and full novels. The font is big, the pictures are great, and the kids feel like they are reading a big book when in reality it's about 30-40k words.
I look forward to giving it to my eight-year-old to read by himself.