Alastair Reynolds Quote

Are you sharpness personified?
Khouri poured herself a few final sips of coffee and then left the rest of it on the stove for when she got back. Coffee was her only vice, one acquired in her soldiering days on the Edge. The trick was to reach a knife-edge of alertness, but not be so buzzing that she could not point the weapon without shaking.
I think I've reduced the amount of blood in my caffeine system to an acceptable level, if that's what you mean.

Chapter 2 (p. 27) - Revelation Space (2000)