I don't know what goes into the aroma of the New York subways.

"New York Subway" is a fragrance unlike any in the world. If you woke me up in the middle of the night with a vial under my nose, I could tell you exactly what it was -- but what is it, and where does it come from?

Diesel oil and tar are its primary components, which doesn't make much sense, since I think the trains are electric -- aren't they? -- and the subway tunnels are concrete. Above the diesel and tar are the more expected smells of a giant city: garbage, old urine, sweat, damp wool, coffee, food.

Several years ago I toyed with the idea of moving to New York, and spent a week with friends in Brooklyn, just poking around the city. At night I'd sleep on their pullout sofa and dream about spending hours scrubbing out subway stations on my hands and knees. Washington, DC keeps its subway stations almost unnaturally clean; why can't New York? (Obvious answer: New York's system has many times the number of subway stations, many times the number of riders, and is about 100 years older than Washington's.)

This morning I shared the elevator at Clark Street with a father and daughter, and the little girl picked an empty potato chip bag up off the floor. As she moved to pick up another piece of trash, her father said, "Sweetie, you don't have to clean up the whole car." "But I want to," she said.

What I Read This Week

Olen Steinhauer, THE TOURIST. Matt Baldacci of St. Martin's put the advance copy of this book in my hand at BookExpo America in May, saying it was the best novel they were publishing next winter. I wouldn't disagree; it is certainly the best spy novel I've read this year. Milo Weaver is a former covert agent trying to live a normal life as an office employee of the CIA. A legendary international assassin tracks Milo down, not to kill him but to find out who has killed the assassin himself -- he's dying of AIDS. Milo's search takes him back to the deepest secrets of his own life in a novel whose twists continue to the last page.

Michelle Gagnon, BONEYARD. FBI Agent Kelly Jones investigates the discovery of several sets of bones, buried in the Berkshires. Someone's been killing young gay hustlers, and soon it seems that a second killer is at work. I figured out the killer pretty early on, but this is still solid entertainment from an excellent new writer.

Marianne Wiggins, THE SHADOW CATCHER. A dazzling novel that weaves historical fiction -- the story of turn-of-the-century Western photographer Edward S. Curtis -- with a fantasia on Wiggins's own life. Gorgeous writing and a gripping story, and I wished it had been twice the length.