I happen to have been looking at IBM typewriter fonts recently -- https://archive.org/details/IBM-SelectricIITypewriter-Correc... -- so I can say it's actually Courier; the uppercase A is an easy giveaway. You can see all the other body fonts there too; Light Italic for the italics, except for some keywords at the start of lists which are Courier Italic; the page headers are Letter Gothic, as are I think the headings (though I thought it was lowercase Orator at first so I think these fonts are all running together for me).