This book was like the Bible to me during my two pregnancies. It has information about how you should feel when you're pregnant, while you're giving birth and for the next six weeks afterwords.
The book also focuses on how the baby inside of you is changing and growing. It explains feelings that you may have and illnesses that come and arise. The What to Expect When You're Expecting book explains tests that may be done and what you can expect at doctor's appointments.
This series, which include, What to Expect the First Year and What to Expect the Toddler Years, are very descriptive of steps in your child's life. It has a section at the back that explains common illnesses and what to do if you're baby is sick. Don't take this advice over your physicians however. The doctor always knows best.
I would recommend this series to every parent and soon to be parent. This is a great way of knowing what to expect and a great guide for knowing what to do in many different situations.