Tepper is not an especially subtle author. When she has an agenda (as she invariably does), she ensures the reader knows about it. At great length. Whether this affects your enjoyment of an otherwise well-written and thoughtful piece of SF really depends on your own levels of patience.
A (very) loose sequel to Tepper's classic 'Grass', this is a tale of religion gone wrong, and the attempts of a small group of individuals (and their frankly creepy god-creature) to put it right. The pace varies, but there are enough twists and interesting ideas to keep the reader guessing, and the good guys are well-rounded if sometimes a little bland. The bad guys suffer from, quite simply, being bad, and Tepper wastes no more effort on them than it takes to explain why their world-view is wrong.
Originally published over ten years ago, this is not Tepper at her best (for that, read 'Grass'), but it does contain all the elements that make her one of the most challenging writers in her genre: not big tech SF, but SF dealing fundamentally with human societies and human relationships. You may disagree with her view of what makes mankind tick, but you can't deny that it is passionate and uncompromising. Recommended.