This book (as well as the whole Narnia series) is a fantasy story that is appropriate for children. Both children and adults can benefit from reading this book, however.
In a line: Lucy learns to follow Aslan even when she doesn't want to, and even when she must do it alone. In depth: The Pevensies return to Narnia to help the Narnians retake their land from greedy and corrupted men that have overtaken it. Symbolism: Lucy's struggle is that of all Christians -- she must go against popular belief, and even against the will of her friends and family to follow Aslan's will. It isn't easy and it isn't comfortable -- it makes her siblings angry, even -- but, in the end, she knows that it is the right thing to do.
"It's not Man's country but it's a country for a man to be King of." --The Good Badger
"Aslan," said Lucy, "you're bigger."
"That is because you are older, little one," answered he.
"Not because you are?"
"I am not. But every year you grow, you will find me bigger."
" You have work in hand, and much time has been lost today."
"Yes, wasn't it a shame?" said Lucy. "I saw you all right. They wouldn't believe me. They're all so"
From somewhere deep inside Aslan's body there came the faintest suggestion of a growl.
"I'm sorry," said Lucy, who understood some of his moods. "I didn't mean to start slanging the others. But it wasn't my fault anyway, was it?"
The Lion looked straight into her eyes.
"Oh, Aslan," said Lucy. "You don't mean it was? How could I I couldn't have left the others and come up to you alone, how could I? Don't look at me like that oh well, I suppose I could. Yes, and it wouldn't have been alone, I know, not if I was with you. But what would have been the good?"
Aslan said nothing.
"You mean," said Lucy rather faintly, "that it would have turned out all right somehow? But how? Please, Aslan! Am I not to know?"
"To know what would have happened, child?" said Aslan. "No. Nobody is ever told that."
"Oh dear," said Lucy.
"But anyone can find out what will happen," said Aslan. "If you go back to the others now, and wake them up; and tell them you have seen me again; and that you must all get up at once and follow me what will happen? There is only one way of finding out."
"Do you mean that is what you want me to do?" gasped Lucy.
"Yes, little one," said Aslan.
"Will the others see you too?" asked Lucy.
"Certainly not at first," said Aslan. "Later on, it depends."
"But they won't believe me!" said Lucy.
"It doesn't matter," said Aslan.
"Oh dear, oh dear," said Lucy. "And I was so pleased at finding you again. And I thought you'd let me stay. And I thought you'd come roaring in and frighten all the enemies away like last time. And now everything is going to be horrid."
"It is hard for you, little one," said Aslan. "But things never happen the same way twice. It has been hard for us all in Narnia before now."
Lucy buried her head in his mane to hide from his face. But there must have been magic in his mane. She could feel lion-strength going into her. Quite suddenly she sat up. "I'm sorry, Aslan," she said. "I'm ready now."
"Now you are a lioness," said Aslan. "And now all Narnia will be renewed. But come. We have no time to lose."
"Welcome, Prince," said Aslan. "Do you feel yourself sufficient to take up the Kingship of Narnia?"
"I--I don't think I do, Sir," said Caspian. "I'm only a kid."
"Good," said Aslan. "If you had felt yourself sufficient, it would have been a proof that you were not."
