This is an amazing book. I agree with all of the positive things every other reviewer has said. I'm not going to waste time repeating everyone. For the folks that have said the book is TOO detailed on the medical pictures and info, I disagree. If you want something that is more of a guide through your pregnancy, get a copy of What to Expect When Your Expecting, or The Expectant Father (I've been finding both informative, and am glad I purchased all 3). As helpful as books like those are, they don't provide the same level of illustrated detail on how it all works. I really appreciate the many 3-D ultrasound pictures showing the progression of growth in the fetus, and the chart (pages 84-85), "The Fetus's Changing Body", which shows the week by week progression of the fetus's different body systems (skeletal, muscular, nervous, endocrine, cardiovascular, respiratory, skin hair nails and teeth, lymphatic and immune, digestive, urinary, and reproductive systems). It is amazing how fast the baby develops.As great as this book is, there is a major printing error. PAGES 65-80 ARE IN SPANISH! I have put in a request for an exchange. I hope it is an isolated error, but I did see one other review describing the same problem (the only other 3 star review). I attached a picture showing page 80 in Spanish and then page 81 is back in English.the replacement copy was sent via free two day shipping after I emailed customer support. The replacement didn't have any pages in Spanish, so it's all good!