The correspondence collected in Additional Dialogue is largely the record of the aftermath of [Dalton Trumbo's] appearance before his Congressional inquisitors. For Mr. Trumbo, the question was how to survive—economically and morally—through the first decade of the Cold War, the McCarthy period, and the years of slow-motion while the silent generation was holding its tongue. The letters are evidence that he survived very well, despite official and amateur persecution that might well have broken a less jaunty spirit.
What is the literary quality of these letters? Well, like many writers, Mr. Trumbo is pretty full of himself, and that gives a good deal of bounce to his private correspondence. That is true when he talks about himself and his own concerns, nor does his courage fail him when he deals with world events; he is always fluent and energetic, and sometimes he is persuasive as well. He makes no claim to be an original thinker in politics or philosophy, but he does give vigorous expression to what one would have thought was the common American ethic, a sort of cranky and pugnacious independence, as its worst naïvely provincial, at its best—as before Congressional committees—manly in its refusal to blubber before our elected bullies….
[It is not] literary considerations,… but the fact that here is a courageous and honorable man [which] justifies publication of his correspondence. (p. 29)
Emile Capouya, "Book Forum: 'Additional Dialogue'," in Saturday Review (copyright © 1970 by Saturday Review; all rights reserved; reprinted by permission), Vol. 53, No. 44, October 31, 1970, pp. 29-30.