The way of shadows / Brent Weeks.

Enhanced descriptions from Syndetics:

A modern classic of epic fantasy, New York Times bestseller The Way of Shadows is the first volume in the multi-million copy selling Night Angel Trilogy in which a young boy trains under the city's most legendary and feared assassin, Durzo Blint.



For Durzo Blint, assassination is an art -- and he is the city's most accomplished artist.



For Azoth, survival is precarious. Something you never take for granted. As a guild rat, he's grown up in the slums, and learned to judge people quickly -- and to take risks. Risks like apprenticing himself to Durzo Blint.



But to be accepted, Azoth must turn his back on his old life and embrace a new identity and name. As Kylar Stern, he must learn to navigate the assassins' world of dangerous politics and strange magics -- and cultivate a flair for death.



The Night Angel Trilogy

The Way of Shadows

Shadow's Edge

Beyond the Shadows



Night Angel: The Complete Trilogy (omnibus)

Perfect Shadow

The Way of Shadows: The Graphic Novel



For more from Brent Weeks, check out:



The Kylar Chronicles

Night Angel Nemesis



Lightbringer

The Black Prism

The Blinding Knife

The Broken Eye

The Blood Mirror

The Burning White