Standing next to Zimbalist, in front of the arched stone door of the shop, a beardless young bachelor holds an umbrella to keep the snow off the old tart’s head. The black cake of the kid’s hat is already dusted with a quarter inch of frosting. Zimbalist gives him the attention you give a tree in a pot.

“You’re fatter than ever,” he says by way of greeting as Berko swaggers toward him, some ghost of the weight of the war hammer lingering in his gait. “Big as a sofa.”

“Professor Zimbalist,” Berko says, swinging that invisible mallet. “You look like something that fell out of a used vacuum-cleaner bag.”

“Eight years you don’t bother me.”

“Yeah, I thought I’d give you a break.”

“That’s nice. Too bad every other Jew in this accursed potato paring of a District kept right on banging me a kettle all day long.” He turns to the bachelor with the umbrella. “Tea. Glasses. Jam.”

The bachelor murmurs an Aramaic allusion to abject obedience quoted from the Tractate on the Hierarchy of Dogs, Cats, and Mice, opens the door for the boundary maven, and they go in. It’s one vast, echoing room, divided by theory into a garage, a workshop, and an office that’s lined with steel map cabinets, framed testimonials, and all the black-spined volumes of the endless, bottomless Law. The big rolling doors are there to let the vans go in and out. Three vans, judging from the trey of oil stains on the smooth cement floor.

Landsman gets paid — and lives — to notice what normal people miss, but it seems to him that until he walked into Zimbalist the boundary maven’s shop, he hasn’t given enough attention to string. String, twine, rope, cord, tape, filament, lanyard, hawser, and cable; polypropylene, hemp, rubber, rubberized copper, Kevlar, steel, silk, flax, braided velvet. The boundary maven has vast stretches of the Talmud by heart. Topography, geography, geodesy, geometry, trigonometry, they’re a reflex, like sighting along the barrel of a gun. But the boundary maven lives and dies by the quality of his string. Most of it — you can measure it in miles, or in vershts, or in hands, like a bound ary maven — is coiled neatly on spools hung from the wall or stacked neatly, by size, on metal spindles. But a lot of it is heaped here and there in crazes and tangles. Brambles, hair combings, huge thorny elf knots of string and wire, blowing around the shop like tumbleweeds.

“This is my partner, Professor, Detective Landsman,” Berko says. “You want somebody to bang you a kettle, let me tell you.”

“A pain in the ass like you?”

“Don’t get me started.”

Landsman and the professor shake hands.

“I know this one,” the boundary maven says, coming in close to get a better look at Landsman, giving him the squint-eye as if he’s one of the maven’s ten thousand boundary maps. “That caught the maniac Podolsky. That sent Hyman Tsharny to prison.”

Landsman stiffens and shakes out the foil sheet of his blast shield, ready for an earful. Hyman lshamy, a Verbover dollar washer with a string of video stores, hired two Filipino shlossers — contract killers — to help him cement a tricky business deal. But Landsman’s best informer is Benito Taganes, the Filipino-style Chinese donut king. Benito’s information led Landsman to the roadhouse by the airfield where the hapless shlossers were waiting for a plane, and their testimony put Tsharny away, despite the best efforts of the thickest courtroom kevlar that Verbover money could buy. Hyman Tsharny is still the only Verbover ever to be convicted and sentenced on criminal charges in the District.

“Look at him.” Zimbalist’s face breaks open at th bottom. His teeth are like the pipes of an organ made of bones. His laugh sounds like a handful of rusty fork and nail heads clattering on the ground. “He thinks I give a shit about these people, may their loins be as withered as their souls.” The maven stops laughing. “What, you thought I was one of them?”

It feels like the deadliest question Landsman has ever been asked. “No, Professor,” he says. Landsman also had some doubt that Zimbalist was really a professor, but there in the office, above the head of the bachelor struggling with the electric kettle, are the framed credentials and certificates from the Yeshiva of Warsaw (1939), the Polish Free State (1950), and Bronfman Manual and Technical (1955). Also those testimonials, haskamos, and affidavits, each in its sober black frame, one from what looks to be every rabbi in the District, two-bit and big-time, from Yakovy to Sitka. Landsman makes a show of giving Zimbalist another once-over, but it’s obvious just from the big yarmulke covering the eczema at the back of his skull, with its fancy embroidery of silver thread, that the boundary maven isn’t a Verbover. “I wouldn’t make that mistake.”

“No? What about marrying one of them, like I did? Would you make that mistake?”

“When it comes to marriage I like to let other people make the mistakes,” Landsman says. “My ex-wife, for example.”

Zimbalist waves them over, past the stout oak map table, to a couple of broken ladder-back chairs beside a massive rolltop desk. The bachelor can’t get out of his way fast enough, and the boundary maven grabs him by the ear.

“What are you doing?” He seizes the kid’s hand.

“Look at those fingernails! Feh!” He drops the hand as if it’s a piece of bad fish. “Go, get out of here, get on the radio. Find out where those idiots are and what’s taking so long.”

He pours water into a pot and throws in a fistful of loose tea that looks suspiciously like shredded string. “One eruv they have to patrol. One! I have twelve men working for me, there’s not a single one of them who couldn’t get lost trying to find his foot-fingers at the far end of his socks.”

Landsman has put a lot of work into the avoidance of having to understand concepts like that of the eruv, but he knows that it’s a typical Jewish ritual dodge, a scam run on God, that controlling motherfucker. It has something to do with pretending that telephone poles are doorposts, and that the wires are lintels. You can tie off an area using poles and strings and call it an eruv, then pretend on the Sabbath that this eruv you’ve drawn — in the case of Zimbalist and his crew, it’s pretty much the whole District — is your house. That way you can get around the Sabbath ban on carrying in a public place, and walk to shul with a couple of Alka-Seltzers in your pocket, and it isn’t a sin. Given enough string and enough poles, and with a little creative use of existing walls, fences, cliffs, and rivers, you could tie a circle around pretty much any place and call it an eruv.

But somebody has to lay down those lines, survey the territory, maintain the strings and the poles, and guard the integrity of the make-believe walls and doors against weather, vandalism, bears, and the telephone company. That’s where the boundary maven comes in. He has the whole strings-and-poles market cornered. The Verbovers took him up first, and with their strong arm tactics behind him, one by one the Satmar, Bobov, Lubavitch, Ger, and all the other black-hat sects have come to rely on his services and his expertise. When a question arises as to whether or not some particular stretch of sidewalk or lakefront or open field is contained within an eruv, Zimbalist, though not a rabbi, is the one to whom all the rabbis defer. On his maps and his crews and his spools of polypropylene baling twine depends the state of the souls of every pious Jew in the District. By some accounts, he’s the most powerful yid in town. And that’s why he’s allowed to sit down behind his big oak desk with its seventy-two pigeonholes, smack in the middle of Verbov Island, and drink a glass of tea with the man who collared Hyman Tsharny.

“What’s the matter with you?” he says to Berko, casing himself with a rubbery squeak onto an inflatable donut cushion. He takes a package of Broadways from a cigarette clip on his desk. “Why are you going around scaring everybody with that hammer of yours?”