This book, years in the making, is written mostly for girls and young women so they can have a better understanding of why men often act the way they do. Women will probably figure it out eventually but it's great to be armed with knowledge and insight. So if a woman comes across a guy with similar characteristics found in this book, she'll recognize the behaviors and know she's not "just imagining things", "making a big thing out of nothing", etc. - the way a woman is often told (by a guy) when she points out some character flaw he has.
The understanding of a negative situation often helps us to make peace with it and experience forgiveness - which ultimately benefits everyone. Being informed will, hopefully, help us make better choices in life.