I think that this book will become a classic Steam-punk book in time.Miéville has invented a world where the majority of life takes place on the Railsea, a huge swathe of criss-crossing railway lines with multiple lines intersecting, and with cities dotted throughout the plain. The landscape that the trains inhabit has a series of nasty animals that seek only to eat each other, and any human foolish enough to step on the soil. Sham is an assistant to the trains doctor on a mole hunting train, after Moldywarpes in the southern ocean. After hunting they come across a wrecked train and Sham makes a discovery in the wreckage. Lots of other people are interested in what he has discovered and he ends up being chased and kidnapped before reaching the end of the line. The captain of the train has a desire to catch the great white Moldywarpe that took her arm.Has echoes of Moby Dick about the book. Miéville has invented a complete and plausible culture and language in the alternative world, and the plot hangs together well.