Being small board books, they were great for a first book because our son could hold them and even chew on them and really get interested in the idea of a book. He could hold one while we read another. Being simple picture books with a cute baby as the focus, the books seem to hold an infants attention and we had lots of opportunity for interaction. I talked a lot about what the baby was doing and feeling -- as well as the other objects on each page.
When our son started standing and walking, he started imitated the actions in "I Can." At 23 months, he still picks these books up and goes through them by himself from time to time. The books have gotten so much use that they are falling apart!
I'm online looking for the boxed set to give to friends with a newborn...