I didn't enjoy this one quite as much as the other books by Desmond Bagley. Part of it was that the hero didn't really seem all that heroic. I read it while I was in Cambridge, and it was good enough to make me want to stay up and finish it off, but I felt a little disappointed. It wasn't bad, don't get me wrong, but not as good as the others. The detail about Iceland was very well written, and if I hadnt got quite annoyed at Stewart for being not particularly heroic, I would have thought him quite a good character. I just have a preference for spies to be heroes. It was a great plot though, and even if I'm not a great lover of women who just provide a rather 'dumb blonde' sort of attraction, this was not quite as much of a 'dumb blonde' as I've noticed in most books of this era.
I definitely recommend Desmond Bagley, though I don't think this is one of his best works.