Death
Death is a concept with which Herzog struggles throughout the entire novel. He feels governed by death; bliss is, for Herzog, spoiled by its impermanence. He is haunted by the death of his mother, still feeling the need for a caretaker. This death overshadows the novel, and by processing it Moses overcomes a major mental hurdle. When the novel opens we find Moses in a chronological void; he is discontent with his present, terrified of his future, and haunted by his past. Throughout the book Moses learns to cope with death and exist with the awareness of it while facing and enjoying his present. Death represents for Moses a time of absolute truth, and by facing it he puts to bed the old horrors of his life and starts afresh.
Sex
Herzog, in addition to his two marriages, enjoys many casual affairs. The most prominent of his mistresses is Ramona, to whom he turns for spiritual comfort. He believes her to be a completely sexual being and takes joy in the lack of responsibility their relationship demands him to shoulder. For this reason he finds it unbearable when she tries to impose upon him her opinions of his personal life. He writes in his letter to her that she has "the complete wisdom. Perhaps to excess" and worries about his vulnerability to her charms. He calls her a "sexual priestess" and flees New York to escape her potency. In this way Ramona's first encounter with Herzog reflects his depressed paranoia, and their subsequent meetings document his softening.
Ramona is almost a theme unto herself in this sense, but the mention of and resulting comparison to Herzog's other mistresses illustrates Herzog's desire to trivialize their relationship. This in turn represents Herzog's traumatic state and phobia of intimacy. His first affair, with Sono Oguki, takes place during his separation from Daisy. At the time Herzog is grappling with guilt for the failure of his and Daisy's marriage - a failure based in reality upon their simple incompatibility. He is in a bad state, drinking heavily and regularly using sleeping pills. During this period he becomes infatuated with Madeleine.
It seems that Madeleine represented for Herzog a way out of his failures. He did not anticipate having to cope with her demanding nature or fanaticism. He continued to enjoy extramarital sex during their marriage. Casual sex is a safe haven for Moses; it is a turning point when in Martha's Vineyard he experiences guilt at the notion of taking advantage of Libbie's kindness. In refusing himself the escape of an affair, Moses take a step forward. The intensification of his affair with Ramona similarly signifies his healing.
Family
Herzog is idealistic, living very much in his own head. He feels bombarded by phantom responsibilities and compelled to assume an identity. We learn through his reminiscences that he was educated, that his father was an ineffectual man who failed at almost everything he attempted. He weakly protested when scolded, as often he was by Moses' Aunt Zipporah, a most imposing and powerful woman. Moses' father is referred to as Jonah, while his mother is simply known as Mama or Mother Herzog. She seems to be more of a figure than a person to Moses, all the way until her death when Moses was aged sixteen. A flashback in the book recalls this: "She only pitied me, her orphan, understood I was a gesture-maker, ambitious, a fool; thought I would need my eyesight and my strength on a certain day of reckoning. A few days afterward, when she had lost the power to speak, she was still trying to comfort Moses." His mother's selflessness explains Moses' lack of consideration for his wives and lovers. Identifying with his father, he views regular women as caretakers and views powerful women, like Zipporah, as dangerous bullies. His family history explains his commitment to his work and his preference for casual affairs, as well as the resentment he bears toward Madeleine for the failure of their marriage. Furthermore, while we meet one brother and learn a considerable amount about the other, very little is said of his sister.
Identity
As touched upon above, Moses undergoes a severe identity crisis which flavors his thoughts. As his self-confidence rots, he turns to face after face in search of retribution. When faced with an overwhelming concern for his mental stability, he demonizes those around him, attempting to justify his actions by victimizing himself. He refers to Madeleine as "masterful," assures himself that she had been psychopathic from the start and does everything in his power to assure himself he has not driven her mad. Feeling his actions are constantly questioned, he grows defensive, and expresses disdain for all who attempt to challenge his actions. By clinging to his deranged logic, he is constantly lying to himself, burying his identity. The turning point for this crisis happens late in the book, when Herzog flashes back to the memory of his rape. It is clear that he has hidden this from himself for years. Only after he discovers the details of his true victimization does he cease his wallowing and reassert himself as a man. For much of the novel, however, Herzog completely avoids his identity.
Letters
The letters that punctuate Herzog are not only therapeutic for their writer; they represent the trauma he is enduring and the way in which he distances himself from the world. Unable to face direct confrontation, Moses voices his frustrations in the most remote manner of communication, a mode that allows him total control over his message. The fact that he does not send them signifies his lack of trust in his own convictions, propelling his search for true validation. It is Herzog's constant questioning of himself that heals him, explaining why he resents the opinions of others. Finding himself powerless to stop writing letters, Moses experiences an important catharsis, and when he finally finds peace at the end of the novel, his urge to write them disappears. Throughout the novel the letters serve to illustrate for us the life of Moses as he sees it, and thereby walk us through his conflict and his resolution.
Nature
Nature seems to represent for Herzog the madness for which he lusts. The novel opens depicting him in harmony with nature, having reached some degree of peace. We see this again as he stands on the dock waiting for the ferry, embracing with longing the sun and the sky and the sea. In his flashback to the scene with Shapiro, Moses talks about looking beyond the table at the afternoon, admitting he had "seldom heard anything so beautiful as this massed continual harshness." "Harsh" is a word Moses uses repeatedly to describe nature, implying that a part of him longs to confront his demons directly and exorcise them. The avoidant in Herzog, however, fears the harshness and causes him to huddle deep in excuses, laying the blame for his own mistakes on others: "But I am a prisoner of perception...I dwell in yon house of dull boards."
Madness
Herzog describes Madeleine to the reader as maniacal and paranoid, attributing the unhappiness that drove her into Valentine's arms to a mental dysfunction of which he is blameless. He seems truly shocked by her outbursts, assuming that they must have nothing to do with him. The unanimous conviction of the characters he encounters, however, is that Herzog himself is unstable. As the reader is constantly immersed in Moses' perspective, this claim is never made by the narrator. Herzog can, however, be safely termed a first-hand document of the protagonist's battle with madness and the beginning of his healing.
Social Role
Herzog is torn, throughout the novel, between varying social roles he feels compelled to fulfill. Determined to succeed as an academic, he plunges himself into his work in the house in Ludeyville, abandoning Madeleine to her own isolation. Unaware of his own selfishness, he resents Madeleine for the care he takes of her. In a conversation Moses recalls having with Valentine Gersbach, he complains: "...I spend about twenty grand in a year. Everything I inherited." His complaints win little sympathy from Valentine, who is conducting an affair with Madeleine at that point in time and understands her emotional void. "She wants you to admit her importance...You're effing it up with all this egotistical shit," Valentine tells Moses. "It's a big deal - such a valuable person dying for love."
Herein lies the root of Moses' problems. Made egomaniacal from a low and vague sense of self worth, he struggles throughout the novel to fulfill multiple social roles and live up to his own standards. This leads to him committing so heavily to contrasting causes that he is wracked by an identity crisis, a rising schizophrenia which drives him deeper and deeper into lunacy.