Saul Bellow wrote Herzog in 1964 as a tribute to an old style of novel, written as found letters or diaries. Herzog is composed primarily of letters, and concerns the aging Moses Herzog's regrets and disappointments with life and the people around him.
The most important example of symbolism is the text itself; Herzog spends a lot of time thinking about what is wrong and how to address it, and he composes letters in his head to people both living and dead, trying to come to terms with his own feelings. Since the letters are mental instead of physical, Herzog never actually confronts these people; instead, he is using the formal structure of the letters as a way to dissociate himself from the pain and humiliation he has faced. Herzog's constant overthinking and obsessing over details internalizes his struggle, and he does not begin to heal until he is arrested; at that point, with the people around him amazed at his attitudes, Herzog finally understands that he needs to change himself, instead of blaming others.