I know there are a good number of books out there, and you can also read through people's reviews of them (Amazon is an example) which I find helpful. I am in the process of building a "library" if you can call it that because it's still small, but I started out with one book last year "How to Raise a Healthy Child in Spite of Your Doctor" by Robert Mendelsohn, M.D. Then I recently got two other books, "Make an Informed Vaccine Decision for the Health of Your Child: A Parent's Guide to Childhood Shots" by Mayer Eisenstein, M.D., J.D., M.P.H. and "Vaccine Safety Manual for Concerned Families and Health Practitioners" by medical researcher Neil Z. Miller. These last two books are also sold on the thinktwice.com website and the latter book contains an excellent foreword by Russell Blaylock, M.D. (a neurosurgeon). I like how these books are written by professionals in the field with insider knowledge that I find extremely helpful to know!
Some other books I would like to get in the future include "Saying No to Vaccines" by Sherri Tenpenny, D.O., and "Vaccination I$ Not Immunization: The Sanctity of Human Blood" by Tim O'Shea, N.D. I would also like to read a book that just came out called "Vaccine Epidemic: How Corporate Greed, Biased Science, and Coercive Government Threaten Our Human Rights, Our Health, and Our Children". Hopefully I'll add these to my collection in the future too, just some examples you can go on or follow your intuition to find the right sources that resonate with you. I know the internet is pretty amazing with all the stuff you can find. Good luck and may you find what you are looking for!