I've read most of the two books you linked that were put out by the Sears family of doctors, Attachment Parenting and The Vaccine Book. Both books discuss the evidence for and against the recommendations they make. In the case of Attachment Parenting, by the husband and wife William and Martha Sears (a pediatrician and a nurse, respectively), they give mostly anecdotal evidence for their methods based on their own large family and on the experiences of their patients who used the same methods. Their son, Bob Sears, is the author of The Vaccine Book, and he claims to have read just about every journal article and research study on vaccines, and he references many articles in the book, so I feel like there is plenty of research behind the book. He also readily acknowledges that, despite all of the research he has done, there is not enough evidence to conclude that vaccines are inherently dangerous, but also not enough research to ensure that all vaccines are necessary or necessarily safe. I also read the first chapter of Nutureshock and, like you, I was pleased to see its use of peer reviewed studies for making recommendations on parenting. Another favorite science-based parenting book of mine that I've recommended on Moms4Moms before is Bright From The Start.

It would be great if all the research had been done to figure out the best way to raise a child. I think the problem lies in the fact that researchers have only just begun to study child rearing in the past few decades (starting in the 1960s, but not really being effective until the 1980s), as well as the fact that all children are different, and what works for some, even what works for most, won't work for all. The best course of action, in my mind, for parents to take is to be as informed as they can, so that they can then make informed decisions. Read books, review the evidence, talk to other parents, talk to your own parents, then do what you think is best for your child.