Oh, I love labels, as long as they are numerous. I'm an American writer. I'm a Nigerian writer. I'm a Nigerian American writer. I'm an African writer. I'm a Yoruba writer. I'm an African American writer. I'm a writer who's been strongly influenced by European precedents. I'm a writer who feels very close to literary practice in India - which I go to quite often - and to writers over there.

The novelist can't successfully depict such horrifying reality. But she can, and must, try, to bear witness. There are many ways of doing this; the mode I prefer is indirect.

If you see a theme that you might want to take a photo of, you sort of stand there for an hour waiting for it to resolve, waiting for the geometry of a theme to be exactly what you want them to be. That was my process to get photos.

The big idea behind it was to somehow participate in the discussion about justice. What does it mean to be just to the others out there whose lives we do not think about. One of the answers I came up with was simply tell their stories.

So, for a book set in 2006, Open City evades certain markers, while it embraces certain others. Julius doesn't use a smartphone, and he doesn't discuss contemporary US politics in any fine detail.

Not explicitly, no. Compared to this enormous, relentless evolutionary activity in the built environment, writing is small potatoes.

It's an Obama book, certainly. I was delighted, and astonished, to hear recently that he was reading it. It's a book about a new kind of American reality, one that takes diversity for granted. It doesn't celebrate diversity, actually, it just says: this is how we live now.