Sarah Worth leaves her comfortable New England life and successful but philandering doctor husband to join a commune in Arizona led by Hindu leader Arhat. The entire book is told in the form of Sarah's letters and tapes to her friends, family, bank, and dentist; she's also writes response letters to those asking something of the commune (usually for their money back). Sarah is not shy, and reading letters intended for someone else immediately sets the reader on an intimate, almost voyeuristic, foray into the mind and character of our protagonist - first person in its most alive. Sarah is opinionated, hilarious, brutally honest, and humanly, comically flawed. She completely lacks guilt; she is stoic and matter-of-fact. Yoga as a gateway to eastern religious conversion. - Updike is bold. Sarah is disenchanted with her world - she has no place in it, her daughter is grown up, her husband has coldly betrayed her, her mother is dating a sailor - and she turns to Buddhism as an alternative to materialism that seems to be all she has left. It is interesting/ironic that her ability to take half of what she deems hers in the process of running off to the commune is what frustrates her husband most; her greatest power is in the taking, not in the leaving, even though to take could be viewed as materialistic. Buddhism recommends eschewing material goods; in the middle of taking up this philosophy she is in the middle of a messy divorce.
A man writing a woman's letters could read as false, but Updike seemed to feel very compassionate towards his Sarah. It has been written that he used letters as the best way to minimize the narrator's voice. The book is also very comic, ironic. Humor is a clear separator between the author and serious topics. Updike has said in an interview that the older he gets, the harder he gets, the more separated from "earthly struggles", and thus the more comic. Updike has stated that he wrote S. in response to criticism that his women were generally weak, silent; Sarah did move from the control of one man (husband) to the control of another (Arhat); both disappoint in their imperfection.
The book flap describes Sarah as a latter-day Hester Prynne - the unusual title is a nod to Hester's "A", is also how Sarah signs some of her letters, and is a reference to the snake in the garden of Eden. "The Scarlett Letter" is a classic novel of religious concerns: sex, sin, conscience, morality. Critics consider three of Updike's novels to be investigations into Hawthorne's themes. "S" turns Hawthorne on his head: Dimmesdale is the villain; Arhat is a charlatan. In Puritan society, women are temptation and are thus fonts of evil; in Buddhism, women are goddesses. Hester's forest is a foil to Sarah's desert. Like Hawthorne, Updike was concerned about religion and sexual transgression; in one interview, Updike stated, "there is some deep alliance between the religious impulse and the sexual. Both are a way of perpetuating our lives, of denying our physical limits." In the Bible sex = knowledge; this was clearly also Sarah's assumption in her various sexual explorations.
**spoiler alert**
At the conclusion of the novel, Sarah was not taken to lunch by the commune nor by her husband. She is living life on her terms.