Fifty years ago today, on October 16, 1962, President John Kennedy was shown aerial photographs of offensive Soviet nuclear weapons in Cuba. Thus began the Cuban missile crisis and history’s highest-stakes game of chicken.

During the following thirteen days, my grandfather, Paul Nitze, then a high-ranking official in the Defense Department, was a member of ExComm, a small group of men who debated how the United States should respond. The President secretly recorded many of the conversations, but Nitze was the only participant authorized to take notes.

A few years ago, while researching a book about Nitze and his long-time friend and rival George Kennan—“The Hawk and the Dove: Paul Nitze, George Kennan and the History of the Cold War”—I came upon these notes, sitting in a box, behind a boiler, in a building at the Johns Hopkins School of Advanced International Studies, a school which Nitze had helped to found and where he worked when not in government. I quoted from them in the book, and donated them to the Library of Congress as part of a large collection that is now available for viewing. In honor of the anniversary, I’m also putting them all online today. Nitze’s handwriting isn’t great, and my digital photography isn’t either. But they provide a real-time glimpse at decisions made during a moment of terror.

The notes cover thirty-nine different meetings, beginning with one held in the office of Undersecretary of State George Ball. (Scroll to the bottom for a full slide show of notes from that first meeting.) And, from the start, they show Nitze’s mind—clinically—working through the options. “1. Facts 2. Alternatives 3. Systematic review of consequences,” he writes.

They also, very early on, show that the group understood that the fundamental choice was whether to strike the arsenal or not. And, if the U.S. did strike, could it contain the consequences? After Nitze talks through the game theory, former Secretary of State Dean Acheson, Nitze’s former boss and mentor, replies, “Deadly serious either way.”

Some of the notes are from meetings that were recorded and for which Nitze’s jottings will thus provide relatively limited value for historians. But little or no record exists for other meetings that Nitze attended. And there are also deeply personal, almost diary-like jottings. Early in the crisis, for example, Nitze wrote out his views in longhand. He explained the likely Soviet responses, and our responses to their reactions. He writes that he would propose a strike against a “minimum number of targets” if the blockade had not succeeded in two or three days. “I believe it highly unlikely that the Soviets would strike [the U.S. Strategic Air Command] under conditions where S.A.C. is fully alerted. If the surviving Cuban missiles are used against the U.S. I would invade Cuba, not use weapons against Cuba. It might then, however, be necessary to make a purely compensatory attack against the U.S.S.R.” At the bottom, he signed his name.