This, the child's version of The Lion, the Witch and the Wardrobe, is an excellent way to introduce your children to the classic books by C.S. Lewis. It covers the basic points of the original book in a much shorter version but with the same great lessons. It is in storybook format with beautiful, life-like illustrations.
I really liked this book, and surprisingly, so did my 6yo and 4yo daughters. I thought they would be afraid of the pictures of the White Witch, but they were not and they enjoyed the story.
I do recommend discernment in that it might be appropriate for some 4yo and not for others. Also, I skipped some of the story because I thought it would be too scary or too hard for them to grasp. So while I would highly recommend this book to 6-year-olds and up, this is a book that the parent should read before reading to their child.
I give this book a 4 only because it may not be good for every child. However, the content is, of course, excellent!