As the sun sank toward the horizon, the empty, blue enormity of the Pacific washed over three small whale boats. The Essex had sailed from Nantucket a year ago, scouring two oceans for the whale oil that drove the island’s economy. On November 20, 1820, the ship was 2000 miles west of South America, over 1200 miles from the nearest island. That day, an eighty-ton sperm whale escaped the pursuing...