I've previously reviewed books about preemies here and here.
If you have been looking for books about preemies, you have probably come across the following books: The Preemie Primer: A Complete Guide for Parents of Premature Babies-From Birth through the Toddler Years and Beyond by Jennifer Gunter, MD and Preemies: The Essential Guide for Parents of Premature Babies by Linden, Paroli and Doron. B. bought both of these books after LB was born. According to B., both were disappointing because they lacked medical detail, and she would have preferred having a medical textbook about premature infants (this is, after all, the woman who was mistaken for a NICU worker for an embarrassingly long period of time by a group of med students).
I only wanted medical information on a need to know basis, but since I was so forgetful, it was nice to have a reference at home. I think if I had to choose one of these books, I would choose The Preemie Primer because I found it better organized for my needs. The Preemie Primer is divided by bodily systems (heart, lungs, eyes, etc.), while Preemies! is divided by time period (first day, first week, hospital, home). Since I was usually looking for information specific to LB's particular medical conditions, it was easier to find the specific information I was looking for in The Preemie Primer. While these books can be useful as you try and formulate questions you want to ask the doctors and nurses in the NICU, I found it better to get my information directly from the NICU. I suspect that the information in these book quickly becomes out of date, and the explanations lack the nuance you get from a conversation from someone working in the field. LB's NICU was a teaching hospital, and our conversations with her doctors often when something like "Some studies have show A and some studies have shown B. At this point we really don't have definitive evidence. My preference is to do X for the following reasons, but some of my colleagues choseY for the following reasons, it's really a matter of preference." Good doctors who you trust are worth a million books. Seeing doctors and nurses at work in the NICU made me realize the mix of science and art that goes into caring for babies. Preemies can be so complicated and their symptoms often don't have clearcut causes, and no book can really explain that complexity, so the purpose of the books are to provide some basic information and some sense of control.