I thought this was a more together book from Rankin. Some of his more recent efforts have run a bit out of steam towards their ends, but this was more coherent throughout. Well, I say coherent. The plot involves various characters travelling backwards and forwards through time and doubtless has a few holes in it, but glossing over that, it does build to something approaching a climax, rather than petering out halfway through as some of his other more recent books have done.
It would be intriguing to know what first time readers of Rankin make of this, given his tendency to drop in characters and themes from previous books - Hugo Rune, Barry the Holy Guardian Sprout, the lady with the straw hat, the Flying Swan, etc. Whether that would add too much to the confusion I'm not sure. Doubtless Rankin fans will love it. I thought it a bit of a return to form. Let's hope he keeps it up.