For someone who reads most of the time—on the train, in the library, at the dentist's—this is not an easy question to answer. Reading occurs at various levels of concentration; for me, focus is determined by the environment as much as the book. And what I'm reading now or in the past few years is not psychologically defining, I suspect, any more than what happens to be on my iPod is: both are subject to randomness, convenience, and passing attraction. Roland Barthes said he divided his reading in two branches: for work he read at the desk; for pleasure, on the bed. That's a bit too dichotomized as it leaves out the armchair and the waiting room, and I usually fall asleep while reading on the bed, but the basic idea is fair enough. A different place for different reading.