Stephen Baxter is a fascinating teller of tales, although, for me, his highbrow scientific monologues rarely blend well with the plot. In Ring - the last of the Xeelee sequence - his ensemble cast includes several characters who regularly pause the action to make turgid lectures to their colleagues. Some of this science is integral to the story - of the ultimate fate of the Universe - but the interludes are like blocks of concrete around the feet of something of otherwise mercurial pace and, for the average reader (i.e. one without a PhD in astrophysics), they are a hindrance.
Baxter has big ideas and a brilliant imagination, which makes up for the fact that his characters are inclined to be a little unbelievable and repetitive. In Ring, as in his other books, he throws together a disparate group of individuals and explores their adjustments to each other and to dramatic challenges and events, It doesn't quite come off, because, beneath the surface, it seems they weren't really that dissimilar.
Those criticisms aside, Ring stands alone as a work of vision and innovation, which left this human reader feeling very appreciative of the solidity of planet earth. There are some neat links to earlier Xeelee stories, such as Flux and Raft, and, overall, it is gripping stuff on a cosmic scale. Skim the science lessons and you won't be able to put it down.