Dr. Karl Pedersen, a mystic and physician famous for instinctual diagnoses. He adopts Jesse as a substitute for his own children, both of whom are considered geniuses but neither of whom shows any promise in the field of medicine. As head of his own clinic as well as of his family, he is a completely domineering figure. What he considers necessary discipline his children maintain is an attempt to devour them. When Jesse finally runs away from the destructive demands of his adoptive father, Dr. Pedersen pronounces him dead.
Mary Pedersen, an ordinary woman who has become obese and addicted to alcohol because she cannot live up to her husband’s standards of perfection. She enjoys Jesse because he alone is willing to talk to her. She joins him when, having seen his own face in a mirror as that of a fat stranger, he flees to Buffalo. Mary is weak-willed, however, and returns to Dr. Pedersen and to imprisonment within her widening flesh.
Hilda Pedersen, a brilliant thirteen-year-old who feels ugly in the eyes of her father. Knowing that she is a mathematical prodigy is little comfort to her in the face of his unconcealed rejection and her mother’s reference to her as a freak. She is often on the verge of unconsciousness, torn between their dislike for her and the mystery of her wizardry.
Frederich Pedersen, Hilda’s seventeen-year-old brother, who feels that his music composes itself. Unfortunately, his gift of special sensitivity is considered of no use to the world of medicine, and his father goes looking for a truer son in Jesse.
Talbot “Trick” Waller Monk, a thirty-year-old laboratory section man for Dr. Cady. He is capable of such bizarre insensitivities as eating a boiled portion of human flesh. He also writes poems in which no people appear. Although he suffers from a rheumatic heart condition, he attacks Jesse physically as if suicidal. He tells Helene that he is in love with her but, at the same time, says that love is illusory. He reappears in New York City, now a famous poet (author of the title poem, which prefaces the novel, and of another on the body’s central nervous system, titled “Vietnam”). He has become a pathetic, unpredictable drug addict.
Dr. Roderick Perrault, the chief resident at La Salle Hospital and a specialist in brain cancers. He takes Jesse as his apprentice, with expectations that Jesse will become his junior partner. He is interested in the possibility that a brain might be transplanted and, with it, the original mind still intact and operative. The issue, though a scientific one, affects Jesse’s personal sense of shifting identity as well as the struggle within him between fate and free will.
Dr. Benjamin Cady, Helene’s father, who argues that a mind, having memory and personality, is distinguishable as separate from the brain. He and Dr. Perrault seriously debate these differences and whether, after the body’s death, certain brains should be preserved by the government for the good of the nation. His second marriage, at the age of sixty-seven, helps liberate Helene from a lifelong fixation on her father.
Helene Cady, a daughter who has been extremely close to her father since childhood. She wants Jesse to promise they will have at most one child. Later, she is tempted to abort their first daughter. After Michelle, their second daughter, is born, she weeps, feeling that she is a failure because she cannot have more children. With men other than her father, she has always felt uncomfortable, and at times she is hostile toward the inner workings of her body.
Reva Denk, a stranger whom Jesse meets accidentally in 1956. He is immediately attracted to her. She resists him until she requires an abortion. He refuses but offers to act as father to her unborn child because he likes to think that he is dedicated to life. He follows her to the commune where she lives with the father of that child and his wife. When Reva says that Jesse’s attention is suffocating, Jesse begins to slash himself with a razor blade.
Michelle (Shelley) Vogel, Jesse’s daughter, who calls herself an unadopted baby in a letter written after she deserts her family. In 1969, she is bailed out of a county jail in Toledo, only to wander off again to Florida, Texas, and Toronto. She is with Noel, a draft dodger on drugs, who has reduced her to a state of degradation in their Canadian commune. When Jesse finds her, she seems to be suffering from hepatitis and hunger. He refuses to let her die and rows her back to the United States in a fifteen-foot boat.
Noel, Shelley’s companion in Canada. He finally agrees to sell her body back to Jesse at the same price he would pay for a corpse: five hundred dollars. He says that he once saved her from jumping off a bridge but that he has no personal feeling for her.