One of my friends recommended this book after she read one of my four-year-old son's stories. She thought he might like it and be able to relate to the mouse. She was very right. My son scares away scary monkeys and other terrifying creatures in his stories. He certainly can relate to this mouse.
I read that Julia Donaldson originally planned for the gruffalo to be a tiger, but had to create a gruffalo to fit her rhyming scheme. I am so glad that she did. The mystery of the gruffalo builds the suspense of this tale. This book pays homage to Sendak's "Where The Wild Things Are", but still stands easily on its own. The rhyme and meter are well done and the conclusion is quite satisfying.
The illustrations by Axel Scheffler also pay homage to Sendak, but they, again, stand very well on their own. All the expressions and emotions of the mouse are conveyed by the eyes, tail and arms -- everything else remains almost static. It is a very effective technique. The gruffalo is scary, but not too scary; he does look as if he might be tricked by a clever mouse.
All in all, I'm glad my friend recommended this book. It makes a delightful addition to my son's library.