The story is fairly simple, and has been repeated many times in many different ways by many different authors since: for me, Piece was the first to tell it. Alanna does not want to be a "Lady". She doesn't want to go to a convent and learn embroidery and other "lady-like" subjects. She wants to be a warrior, and fight, and defeat evil! So she takes her twin brother's place as a page (he wants to be a knight as much as she wants to be a Lady) and begins her journey to knighthood. She's keeping her identity - and femininity - secret, though a few do discover it, and along the way learns a lot about being true to herself, while also becoming a totally kick-ass heroine.
There's a bit of magic involved (actually, a lot) but nothing is easy for her, even the things she's naturally good at have to be worked on and improved - which is, of course, another lesson for the young who will have no idea they are learning as they are reading. I certainly didn't at the age of nine, I just thought it was a cool story. It's only now that I realise how much these books influenced me to be myself when it would have been easier to not be.
Reading this over ten years since the first time, I can't help but notice the simplicity of the writing. This doesn't make it bad, and maybe it's just a phase I'm going through but I'm really craving beautiful prose, where the writing is as important as the story. The book is written for a young audience, of course, and I never thought there was anything wrong with it when I was young. To be honest, there isn't anything wrong with it, I'm just being picky. In her later books the writing flows a little more easily as Pierce settles into her style, it's just here that it's a little stilted. That's the only reason I've given it four stars instead of five.
I said before that Alanna was the perfect heroine to me as a young child - well, she still is. If I ever have a daughter I will give her these books, if only because they show that just because you don't fit into the stereotype of being a "girl" (liking dolls and makeup and other designated "girly" things) does not mean that you are not one.