A collection of lectures delivered by Dr. Oppenheimer over a period of eight years from 1946 to 1954- this gives a panorama of the thought formation and the humbly offered statements of a dedicated liberal and a true scientist. In reading these one puzzles again over his loyalty questioning last year and the irony of it, for these are the words of a man whose being naturally allies itself with actual human progress. Though all part of the same principle, different themes emerge in the lectures- freedom of inquiry, the wrongness of the totalitarian state as an inhibitor of individual freedom, the evil of secrecy that must nevertheless be balanced by our power to withstand the enemy. Two lectures show how he makes them part of different topics. Discussing the relation of atomic energy to American policy in the title lecture, delivered in 1948, Dr. Oppenheimer touches on a basic opposition of forces in atomic development; though the new force was developed through freedom of inquiry it appeared as its opposite- coercion. Knowing where its ideals lie, the U. S. still has the difficult Job of sustaining power while maintaining freedom. In another lecture Atomic Weapons and American Policy there is a grim look at reality that reveals the hazards not only of soft pedalling the dangers so that the populace will not worry, but of a mushrooming arms race, the peculiar characteristic of which is a negation of our atomic force by an opposition that may be less in quantity but hardly less effective in quality. There is little presumption here to Judge the steps we must take for a secure, free future, but the principles to be used as directives become plain as one reads Dr, Oppenheimer's lectures.