Lansing Lamont, Journalist and Historian of Atomic Bomb, Dies at 83

Lansing Lamont, a journalist who was credited with writing the first popular account of the building and testing of the atomic bombs used in the attacks on Hiroshima and Nagasaki, died on Sept. 3 in Manhattan. He was 83.

The cause was cancer, his wife, Ada Jung Lamont, said.

Mr. Lamont, the author or editor of several books, was a Washington correspondent for Time magazine when he conducted the interviews and gathered the information he used in his book “Day of Trinity,” published in 1965, 20 years after the bombings, in August 1945, that brought about the end of World War II.

It described the personalities and sometimes conflicting emotions of the scientists involved in the American program to build the bomb, known as the Manhattan Project; the rudiments of the mineralogy, physics and chemistry required in engineering the device; and the first atomic bomb test at Alamogordo, N.M., conducted on July 16, 1945, three weeks before Hiroshima....