Nathan talks about his brother, Henry Zuckerman, a suburban dentist who had been having an affair with his assistant Wendy.
At this point the narration shifts into the third person, revealing that this "diary entry" was in actuality the eulogy that Nathan had planned to give at Henry's funeral: the operation had killed him.
He also pities his brother, whom he characterizes as a man so desperate to escape his middle-class existence that he preferred death to its stifling stability.
Part II, "Judea," resets the narrative of the novel thus far: in this section, Henry has survived the operation to fix his heart condition and restore sexual function.
Yet rather than resume his previous life, Henry has chosen to abscond to Israel and live in a West Bank settlement.
In Israel, Nathan meets with a variety of Jews who share their diverse perspectives with him, including a crazed fan named Jimmy who accosts him at the Wailing Wall.
Nathan meets the settlement's charismatic leader, who delivers a rabid soliloquy about the importance of settling Judea and Samaria.
He intends to send a message about Jews no longer being beholden to their traumatic history, and asks Nathan to assist him.
Nathan initially cooperates well with the medication, but he soon finds himself tempted by Maria, an English expatriate who lives upstairs with her daughter and diplomat husband.
He explains that it would allow him to fulfill his greatest desire—to settle down as a family man, by marrying Maria, adopting her daughter, and moving to the United Kingdom.
She relates how she searched Nathan's apartment after his death and found the draft of his unfinished novel (which, due to Henry's intervention, now contains only Part V).
She objects that Nathan exaggerated her family in it, inventing character flaws to make them more interesting and serve his own purposes.
As Part IV concludes, it is gradually revealed that Maria's interviewer is not a therapist; he is in fact a ghostly projection of Nathan himself.
Nathan reflects upon Jewish circumcision—which he would have forced upon his son—arguing that the pain of the ritual symbolizes the unfairness and cruelty the child will encounter in the world.
Nathan ends the book by mourning the dissolution of his and Maria's relationship, because it is only in the pages of this novel he has written that they will ever have lived together in love.
It reflects the way in which the author has many germs of ideas, not all of which reach the complete fruition of becoming a coherent work of fiction.
"[5] This book is included in the fifth volume of Philip Roth's collected works Novels and Other Narratives 1986–1991, published by the Library of America.