A book that really set my life on a different tangent was
Natural Childbirth the Bradley Way. I had experienced a spiritual awakening before I got pregnant, but I think I would have gotten "lost" in conventional parenting methods if I hadn't read this book and gone to Bradley classes. Through that, I chose to have homebirths with both my boys, and met my midwife, who has become a great friend. I was also encouraged to attend La Leche League meetings, which gave me the support I needed to parent the way I was deeply moved to: attachment parenting. Which led to unschooling, which led to consensual living...
Before that,
Be Here Now would have to be the book that opened my eyes, spoke to my heart, and helped set me on my path towards enlightenment.