This is one of Silverberg's favorite books, apparently. I found it rather predictable--I figured everything out right near the beginning, and found the main character's failure to pick up obvious hints frustrating. I don't fault the author for this, as in 1969 the ideas in Downward to the Earth were much newer and therefore the average sf fan would be unlikely to pick up so quickly. However, the book is still an enjoyable read. Oh...I guess I haven't told you what it's about. Well, the author was inspired by Heart of Darkness, so if you can imagine a morality story set on an exotic alien world, you have the right idea. And there are intelligent elephant-type creatures. (No that's not a spoiler, you learn that right off the bat.)