Stevie Kincade I really think the one to read is "Timelike Infinity" first. It isn't very long and is imo one of the best Sci Fis of all time. The events of TI are recapped in "Ring" but it will be more enjoyable if you have read that first. Raft and Flux are pretty much stand alone's and their relationship to Ring can be summarized in a sentence or two, where Timelike's relationship is a little more complicated.
Richp My experience was the same as Terry's. As far as this book is concerned, no big deal. As a spoiler to previous books in the series, I speculate it is not.