November-December 1962 letters focus primarily on world politics (Cuba, India v. China), and the work on Monopoly Capital, in particular the Quality of Society chapters.

Letters of winter 1963 include PMS's trip to Latin America and observations thereof, the Irrational System chapter of Monopoly Capital and issues of race, the ongoing debate over the Sino-Soviet split, the split in the capitalist world, and miscellaneous discussions about world politics.

Letters of spring 1963 include discussions of the Cold War, the Sino-Soviet rift, the Business Week article on Baran, Sweezy, and Huberman, the difficulties for Communist parties in the West, the imminence of revolution in underdeveloped countries, the socialist-capitalist struggle, and the pressure on PAB at Stanford, and PMS's essay "Notes on Imperialism."

Letters of second half of 1963 include discussion of the chapter in Monopoly Capital on race, and the relationship of racism in the U.S. to anti-Semitism in Nazi Germany, PAB's trip to Latin America, PMS's trip to Yugoslavia, the Sino-Soviet rift, the threat of nuclear war, material incentives under socialism, and consumer debt.

Letters of 1964 until PAB's death include discussion of the militarism chapter in Monopoly Capital, Lenin's theory of imperialism, surplus vs. surplus value, productivity and socially necessary surplus, and world politics. Last two letters are one from PAB to Harry Magdoff, and one from Leo Lowenthal to Nicholas Baran after PAB's death.