Unlike most gender-issue post-apocalyptic novels, Califia's Daughters shows a world where men have been nearly wiped out. Also, unlike most women-run worlds, there is no serious claim that the disaster was men's fault. Rather, the book deals with some of the issues that arise without painting men or women in a moral light. I would have preferred to have seen the issues addressed in greater depth, however.
This paragraph has a bare-bones summary of the plot. It's minimal but may contain minor spoilers. The story begins when a small valley community (200+ women, 20+ men) is approached by representatives of another community. The strangers make a proposal that has serious implications for the valley, and introduce the threat of war in the region. The valley's leader, Judith, feels that the strangers are concealing something vital. Judith sends her sister, Dian, to secretly investigate the strangers' settlement to see what they are hiding. Dian goes to investigate, having assorted adventures along the way. Upon arrival, she discovers that the strangers have a secret that will shake the foundations of her own people's way of life!!! Then disaster strikes, Dian drops her quest, goes to another town and does a bunch of unrelated stuff. She never actually talks to the strangers about their differences or even gives them too much thought. At the end of the book, the author doesn't bother to explain what happened between the two peoples.
On the whole, I enjoyed the book. It was moderately unusual, had some romance, some humor, some adventure, and other essentials. In particular, it included some good bits of drama. However, I am left with the sense that the plot got sidetracked. The author raised issues in the beginning of the book that were never addressed. We never know what impact the strangers have on the valley's way of life, and there is a looming war that is never addressed. A sequel would greatly improve the course of the story, but lacking a sequel I feel somewhat cheated.