This has been one of my family's very favorite picture books since our oldest was a toddler. It is a beautiful re-telling of a beautiful story with illustrations that complement it nicely and which are very appealing to children. I especially like Tomie de Paola's attention to detail. It's informative enough to be interesting even for adults.
The story tells of Mary's apparitions to an Indian convert, Juan Diego, in Mexico, in 1531. She asked Juan Diego to tell the bishop that she wished a church to be built. On his second visit, the bishop asked Juan to ask "the lady" for a sign. Mary sends Juan back to the bishop with fresh cut roses - even though it's the middle of December. When Juan opens his tilma (like a cloak) to show the roses to the bishop, they discover that Our Lady's image has been miraculously imprinted on his tilma. This tilma has remained intact and is displayed even today in the Basilica of Our Lady of Guadalupe in Mexico City.
The author also avoids some of the mistakes and biases often present in renditions of the story. By explaining how the Bishop interrogated Juan Diego and carefully recorded all the details, the author makes it clear that this story is not a legend, but an actual occurence. (A note following the story also gives information about the miraculous condition of the tilma today - which is amazingly intact after more than 400 years.) The author also seems to have avoided any politically correct bias. I was particularly impressed with his portrayal of the bishop who was a very holy man with a genuine concern for all the people of Mexico.