If you want something that looks like a book, Angry Robot has a sample of Servant of the Underworld to download, which contains the first chapter. Available in Mobipocket, EPUB or PDF.

Or you can also read the first three chapters online at My Favourite Books (they were cut into five parts to make them more manageable, hence the number of links).

In the silence of the shrine, I bowed to the corpse on the altar: a minor member of the Imperial Family, who had died in a boating accident on Lake Texcoco. My priests had bandaged the gaping wound on his forehead and smoothed the wrinkled skin as best as they could; they had dressed him with scraps of many-coloured cotton and threaded a jade bead through his lips – preparing him for the long journey ahead. As High Priest for the Dead, it was now my responsibility to ease his passage into Mictlan, the underworld.

I slashed my earlobes and drew thorns through the wounds, collecting the dripping blood in a bowl, and started a litany for the Dead.