City of Thieves by David Benioff (Plume Book 2008)

"One of the most beautiful passages in literature, you know. His professor had been a famous writer back in his day, but now he's completely forgotten. Radchenko feels ashamed for the old man. He watches him through his bedroom window - Radchenko never leaves his apartment; remember, he hasn't left in seven years - he watches the professor walk out of sight, kicking at the pigeons and cursing them." Kolya cleared his throat and switched to his declamatory tone. "Talent must be a fanatical mistress. She's beautiful; when you're with her, people watch you, they notice. But she bangs on your door at odd hours, and she disappears for long stretches, and she has no patience for the rest of your existence: your wife, your children, your friends. She is the most thrilling evening of your week, but some day she will leave you for good. One night, after she's been gone for years, you will see her on the arm of a younger man, and she will pretend not to recognize you."
Kolya's apparent immunity to exhaustion aggravated and amazed me. I could keep moving only by sighting a distant tree and promising myself that I would not quit before I reached it - and when we got to that tree, I would find another and swear this was the last one. But Kolya seemed capable of traipsing through the woods, orating with a stage whisper, for hours at a time.