Mohrbacher and La Leche League International, The Breastfeeding Answer Book, Third Revised Edition, 2003
This is a hard-core reference book. This is the book our local lactation consultants use. It is the single most complete, amazing breastfeeding resource I have found. Of particular note are the first few chapters, which discuss changes in our knowledge of breast anatomy, and what we know now. Understanding how the breast works puts so many other breastfeeding problems into perspective. Written with the lactation consultant or other support person in mind, the book first addresses active listening and how to ask questions without prying
This reference really does answer most breastfeeding questions, from nursing in the early days to teething, from nursing strikes to weaning, to the practical issues of nursing a toddler. Answers are comprehensive and supported by cited, peer-reviewed papers. Each paragraph in the book has a one-sentence summary in the margin.
Anyone taking breastfeeding seriously, as an art as well as a science, should get this book. You wouldn't take a circuit design class without buying a circuits textbook... similarly, you wouldn't consult a woman on breastfeeding without this book.