An amazing, intense novel by Sheri S. Tepper, Grass is the first in her loosely knit Marjorie Westriding trilogy.

The planet Grass is inhabited by Hippae, malevolent horse-like creatures with powers to control human minds, and Foxen, mysterious intelligent beings. The aristocrats of Grass, the Bons, live in distant estancias in the grass plains, and dedicate their lives to the Hunt, riding Hippae to kill Foxen. The commoners live in Commons, the one section of the planet inaccessible to the Hippae. Somehow linked to the interplay of man and hippae and foxen is a deadly plague sweeping the galaxy, killing men on every planet - except Grass.

The religion of Sanctity, based on immortality through cloning, controls most of human space. They seek to deny the existence of the plague to keep their control of humankind, but secretly they are desperately seeking a cure, if only for their upper ecclesiastical echelons. The dying head of Sanctity sends his nephew, Rigo Yrarier, and his family, Old Catholics all, to Grass to investigate why they have no plague and if a cure may be found there. Rigo's wife, Marjorie Westriding, is soon caught up in the tangled relationship between plague, the gentle Foxen, the amoral Hippae, and the mysterious extinct aliens the Arbai. Can she unravel it all in time to find a cure?

This is one of Tepper's finest works. It is worth reading just for the beautiful descriptions of Grass and its alien and complex ecosystem, it is worth reading just for the religious tension and subtle plotting, it is worth reading just for the wonderful character Tepper has created in Marjorie Westriding, and it is ESSENTIAL reading when you add them all together. An amazing book. Recommended, recommended, recommended.