He fields midnight phone calls from the New Orleans musician Dr. John, and consults Cyril Neville, a member of the Neville Brothers band. He drops in on David Duke, the white supremacist, now living in Austria and as blithely deranged as ever. Mr. Jacobson describes Mr. Duke’s dyed blond hair as resembling “a half-fallen soufflé,” and notes that his teeth are “whiter than buffed Chiclets.”

Sometimes “The Lampshade” is too shaggy. Mr. Jacobson’s visit with a Dominican spiritualist is a less-than-essential moment, and what are we to do with the news that the author has named the lampshade Ziggy? Mr. Jacobson’s laid-back writing can resemble stoner prose, as if he’s fighting an urge to add the word “dude” to his sentences. The lampshade, he writes, “had become the creaking flying saucer of the Holocaust.”

Mr. Jacobson’s book passes a primal test, however. When you put it down, you look forward to picking it up again. This is largely because it becomes an entangling meditation on not merely Nazi atrocities but on the nature of authenticity. It considers, too, other far-flung topics: the history of skinning and scalping humans; the roots of Holocaust denial; New Orleans prisons during Katrina; black funeral traditions versus white ones; Mr. Jacobson’s own Jewish upbringing in Flushing, Queens.

Mr. Jacobson charts how the lurid, almost pornographic idea of Nazi lampshades has percolated through popular culture. He quotes Leon Uris novels and Woody Guthrie songs, as well as Sylvia Plath’s poem “Lady Lazarus,” with its lines about Plath’s soon-to-die body, with its face as fine as “Jew linen” and her skin “bright as a Nazi lampshade.”

Mr. Jacobson spends a lot of time in New Orleans, and his book is yet another bluesy, scuffed-up paean to that city’s wonders. He quotes the Orleans Parish coroner, Frank Minyard  Mr. Minyard is also a central character in “Nine Lives,” Dan Baum’s New Orleans book  describing how Katrina has “shaken things loose,” in ways good and ill.

All the same, Mr. Jacobson doesn’t let New Orleanians or other Southerners off the moral hook. He reminds us that Mr. Duke got 55 percent of the white vote when he ran for Louisiana’s governorship in 1991. He brings his story full circle when he observes how some white Southerners once slaked their own thirst for human taxidermy.

Mr. Jacobson describes the 1899 lynching of a black man, Sam Hose, in Georgia. Then he writes: “Many viewers had approached the ravaged corpse to cut off pieces of his skin to take home as souvenirs. Later Hose’s heart, knuckles, and facial skin were displayed in local store windows and offered for sale.”

Beauty may be skin deep, Redd Foxx reminded us in a vastly different context, but ugly goes clear to the bone.