Computing the progress of a thermonuclear combustion presented quite a challenge, because there was not the simplicity of geometry that one had in the A-bomb. This was quite something. We had the helpful advice of Marshall Rosenbluth, who is still, even now, a leading figure in thermonuclear physics. He had had a lot of experience in computing and advised us on the kinds of formulas that would be of the most use. But where to get the computing done? We didn't have any computing engines. And we called on the IBM people in New York, John Sheldon there was wonderful. And the computer people at the University of Pennsylvania, with John Mauchly, and we were also using the National Bureau of Standards computer. Here it was, using the substantial fraction of the computational facilities of the United States for this work. And I still feel like a 'piker' when I think of how I never put in these thirty-six hour stretches that so many of the lads did, getting their calculations done. But John Sheldon proved the value of that training at a later point in his life, when he drove from Florida to California, across the country, without stopping to sleep.