I'm glad someone else has read it.
Thanks for the answers. I was able to get it as an ebook, so hopefully that will help it spread a bit further.
For those that haven't read it, the first part is a telling of the few hours before Gavrilo Princip shoots the Archduke Ferdinand and indirectly kicks of the first world war. What follows are several short tales in more modern times, where Princip or the ghost of Princip or the idea of Princip turns up in some way. Lots of themes or ideas or motifs are repeated across these stories - if feels to me a bit like trying to find a way through a maze, and occasionally coming across a point that seems familiar, before heading on into somewhere new.
Martin seems very interested in the bits between recorded history, and in the idea that history as we read or hear about it is centred around the acts that people perform, but we don't get to know about the pauses between the acts - the seemingly-inconsequential conversations with others, the doubts and private thoughts of the protaganists. He also focuses on the idea that the language used to tell history obscures it - there are repeated instances of people deciding to act, instead of thinking or talking about acting, and this is present in the first part where Princip refuses to be talked out of the assassination; he just wants the purity of action. I think Martin is out to portray this separation between the solidity of the act and the ambiguity of describing the actions of others.
His language is purposefully blank and utilitarian, often in the form of He says: / She says:, a contrast to the obscuring function of writing about history. There is a lot about personal perspective; for example a mysterious wall appears overnight in Central Park, people who try to photograph it end up with a photo of themselves taking the photo. To try to get around this, one narrator paints the wall, then photographs the painting, but finds he has a photo of himself painting the wall. I think that is the central preoccupation of the book - all perspective is subjective, history tries to describe actions but language obscures those actions. However, I think there is more than that going on, but I'm going to need to read it again to get some of that I reckon. It's very good.