I initially gave this one 4 stars, but then, on my habitual walk to work the next day, I found myself musing on this book so much that I inexplicably took a wrong turning - a wrong turning, even though I've done that same walk every day for 3 months! - and ended up in a graveyard, and not even the sort of graveyard which doubles up as a through-road, but the sort of graveyard which is nothing but a complete dead end, if you'll pardon the pun, and that, to my mind, is the mark of a very very good book indeed. Not the graveyard bit; that's rather inconsequential, although it was also quite a good metaphor, and I do remember thinking that at the time, but the bit where this entire book is about a man whose daily routine is thrown off kilter by an apparently small occurrence - in his case, the appearance of a pigeon - which then has a domino effect, his whole day falling apart around him in a spiralling fractal, and ultimately casts his whole life in a new meaning. And although I wouldn't say that accidentally ending up in a graveyard at quarter to eight in the morning actually had the effect of casting my whole life in a new meaning, it did make me late for work and I missed breakfast. So, for that reason, I feel like this book probably deserves 5 stars.