Not as breathtaking as Titan by the same author, but interesting nevertheless. Humanity brings doom upon itself by bringing a nano-technological gray goo from the Moon that slowly devours the Earth. This is a sad story where there is a very little hope. The first part is especially poignant - destruction of Edinburgh, misery and human stupidity. The interesting thing in Baxter's books is that his characters are full of flaws - not really typical heroes of SF but very much humans troubled by issues. The book is full of technical details regarding space exploration and geology. Large info-dumps are perhaps a nuisance to some but I enjoy them and Baxter certainly makes the subject interesting.
Some issues I had with the book: one particular character behaves in a very unbelievable way - I am taking about a teenager rascal turn into Space Religion Guru, secondly I feel that whole shtick in the end with main character convincing US to give him a nuke, no question asked - that rises some doubts - I understand that it was necessary for a big surprise in the end but still.
In the end - not my favorite Hard SF but certainly memorable. I think I will further my interest into Mr. Baxter's works.