The Einstein Intersection — Samuel R. Delany

In the far-distant future, when Einsteinian and alien universes intersect, the world begins to change: strangely, wonderfully, incredibly.

And the trek of Lobey, an alien Orpheus, across a weirdly sumptuous planet, leads him to the Dove, fabulous love image of a world obsessed; Greeneye, victim of a dead race's millenia-old ritual; and Friza, the dark and silent girl he searched for to the shores of death-- and beyond.