About a dozen floating prisons were anchored in Wallabout Bay between 1776 and 1783, the most notorious of which was the Jersey, moored about a hundred yards off the Brooklyn shore. No one knows for sure how many were held there, or how many died. Historians put the death toll somewhere between 8,500 and 11,500 men (I found no credible accounts of women held prisoner). By my rough calculations, as a percentage of the total population, today’s equivalent would be about 1,000,000 to 1,300,000 dead.

The salient feature of the Prison Ship Martyrs’ Memorial in Brooklyn’s Fort Greene Park is a tall, fluted column. It was designed by the most famous architect of his time, Stanford White, built at huge expense, and unveiled to great fanfare a hundred years after the war ended and the Jersey gave up its last prisoner, was abandoned, and sank. And it’s a failure. Its “eternal flame” in a bronze urn at the top was either extinguished in the 1970s, or during World War II as a wartime security measure, or never lit at all; accounts differ. The bronze eagles that guarded it are in storage in Manhattan, but two may be returned shortly, or may not; accounts differ. Civic groups and city agencies are committed to restoring the monument. While it may not succeed as a public memorial, its peculiar beauty can inspire intense private moments. Underneath the expansive granite stairs is a crypt. Not long ago, I paid a visit.

Two New York City Parks Department employees sawed through a steel plate that had been welded over a copper door to protect the crypt from vandals, and allowed me inside. The tomb was clean-swept and made of bisque bricks. There rested thirteen caskets, each representing a colony. On top of one was a real human jawbone, with teeth, and a red plastic hibiscus, evidently left as a remembrance. It took an effort, but the three of us managed to lift the lid. Inside were bone chips and dust. Whose?

To get a clear picture of the era I turned to, among others, Founding Brothers: The Revolutionary Generation by Joseph J. Ellis, American Scripture: Making the Declaration of Independence by Pauline Maier, 1776 by David McCullough, Common Sense by Thomas Paine, and the original letters of John and Abigail Adams, Jefferson, Washington, and Franklin. Further research led me to firsthand accounts by two former prisoners, Thomas Dring and Thomas Andros. They were written decades after the fact and subject to jingoism and the vagaries of memory. But in them and in other sources tantalizing fragments and mentions abounded. Plagues of lice and smallpox, and the deployment of both in biological warfare on board. Bread that even weevils couldn’t eat. Piles of cash, of cadavers. Boys crying for their mothers. Rum, privateers, mercenaries. Small acts of kindness. Bond market speculation. War widows. Premarital sex. Song, fever, and gunpowder. Rope—how it bound, how it freed. Hemp, and the fortunes it created. The contemporary equivalent might be oil. Transport and communication depended upon it—rigging and sailcloth for seagoing vessels, naval, pirate, and mercantile, including those bearing sugar, spices, and slaves. Hemp oil lighted lanterns, hemp seed fed chickens. The fabric woven from it clothed people, the paper made from it was used for bills, legislation, currency, pamphlets. Cannabis sativa was the raw material of a free press. If the plant’s intoxicating strains and properties had not yet been exploited, its role in colonial life was nevertheless mind-altering.

Reading history, one thread kept pulling at me: how many ordinary people were simply caught in the wrong place at the wrong time, and how they were radicalized by the experience. I was reminded how incredible it is that my country was founded not on race, religion, or borders, but an idea.

What, then, about the dead? They continued to haunt me.

The Society of Old Brooklynites compiled in 1888 a list of eight thousand prisoners said to have perished on the hulks. From it I took the name Ezekiel Rude. Other characters—William Cunningham, Aaron Lopez, George Sowell, and James Forten, for example—I loosely based on the historical record. In the novel they meet different fates than did their real-life counterparts. But what about someone whose name was not written anywhere, someone completely forgotten? What happened to him, and to those whom he loved and who loved him? He is Salt.