Hoyt C. Hottel begins the first interview with a description of his childhood and education in Indiana, Missouri, and later Illinois, where his father was a salesman in the rubber industry. He praises his early schooling and various teachers and subjects at Hyde Park High School. Hottel discusses his entry into Indiana University's chemistry program at age 15 and courses and professors there, before turning to graduate work in chemical engineering at MIT with Walter Whitman; and relationships with Tom Sherwood, Warren K. Lewis, and Robert T. Haslam. His experiences at MIT's chemical engineering practice school-including work at a Bethlehem Steel plant, Pennobscot Chemical Fire Company, Revere Sugar Company and Merrimack Chemical Company-led to work as assistant director at the steel plant and influenced later research directions. Hottel next describes his interest in radiation from gases in relation to industrial furnace design; his decision to pursue doctoral research on flame propagation in hydrogen oxygen mixtures; the reasons he postponed writing his dissertation; and subsequent appointments as fuel and gas engineering assistant professor, Fuels Research Laboratory acting director, and division of industrial cooperation assistant director. As a central part of this interview, Hottel details his experiences while advising US armed forces and national committees during WWII, including work on flamethrowers, incendiary bombs, smoke obscuration, napalm, and fire warfare. He closes the first interview with a discussion of his post-war career at MIT, work on turbine combustion and peacetime fire research at the Bureau of Standards. Hottel opens the second interview with a review of his early experiences as a graduate student and young professor at MIT; he comments on early research, interdepartmental relations, the development of the fuel and gas engineering program, consulting work for private industry, and supervision of graduate students and their research. He briefly discusses his research involving rocket combustion, gas turbines, and Project Meteor, before describing the details of MIT's solar energy research and opinions on solar energy in general. He touches on involvement with the International Flame Foundation before closing the interview with discussion of post-retirement activities, including teaching combustion and radiative transfer courses and co-authoring a book on new energy technology.