This is was the single best book we got for my son before my daughter was born. The lack of words is perfect because we could talk about everything. The pictures are positive but full of the new things my son would need to adjust to. Grandparents paying attention to the baby, the baby crying, the baby nurses twice in only fourteen pages. At the end, they are very quiet so that the baby will sleep and the parents and older sibling can spend time together just the three of them. We "read" it numerous times. I believe there's a newer edition with words but I wouldn't bother.
When I received this book and saw that there were no words, I was pretty disappointed. But once I started giving it dialogue with my toddler (and seeing what else was out there for similar books), I came to love it. It allowed me to discuss things in my own terms and relate better to my child. For example, talking about breast or bottle, different birth scenarios, dad's participation, etc are all very personal and so the narrative needs to change. I found this to be the best sibling book out there for that reason.
My toddler loves this book. We talk about the baby in mommy's belly all the time. We look at the book together and I tell her what the baby is doing and what the big girl (even though it looks like a boy in the book) is doing. Then we look at it and I have her point to the baby. Great book for new siblings!