When a baby is growing in Mommy's belly, children have many questions. From the outside, nothing is visible at first. But what is happening inside is more exciting than any crime novel: How big is the baby now? Can it hear me yet? Does it notice if it's dark outside or if the sun is shining? Does it sleep when we sleep? Lovingly illustrated, this book provides answers: week by week, based on the latest scientific knowledge, yet understandable for four-year-olds.