Nightingale's Lament by Simon L. Green is a cracking good read for on the train, no more, no less. I liked the combination of noir atmosphere, supernatural horrors and the urban setting, and found the story of the singer whose voice made members of her audience suicidal gripping enough, but I also thought I'd read some of the jokes before, and didn't find the characters all that interesting. I'd buy another one from the same series if it was in the shop at a time when I needed to go on another long train trip.
But the real reason I'm mentioning this book is to prod Einar into finally writing that rave review of another Simon L. Green book he promised.
