Dr. Adler is Wilhelm's father. Nearly eighty years old, he is a retired physician who specialized in internal medicine. He had a thriving practice and was considered one of the best diagnosticians in New York. Dr. Adler has a gentlemanly, affable manner, and his friends and acquaintances all admire and respect him. But he has a distant relationship with his son. Wilhelm feels unable to talk to his father, because his father tends to criticize him. Dr. Adler is disgusted by his son's slovenly habits and does not understand why he is such a failure. He refuses to help Wilhelm financially, even though he has the money to do so. Nor does he help his daughter Catherine in her desire to exhibit her paintings in a gallery. He is detached and cold-hearted, not wanting, as he puts it, to carry anyone on his back.
Catherine is Wilhelm's younger sister. They are not close. Like her brother, Catherine changed her given name, to Philippa. She became a medical technician but has ambitions to be a painter, but neither Wilhelm nor Dr. Adler think highly of her talents.
Olive is the woman Wilhelm is in love with and would like to marry. Even though she is a Catholic, she would marry him outside the Church if he obtained a divorce.
Mr. Perls, a German Jew, is a friend of Dr. Adler. They have breakfast together, with Wilhelm. Perls used to be a hosiery wholesaler. Wilhelm takes an instant dislike to him when they meet: "Who is this damn frazzle-faced herring with his dyed hair and his fish teeth and this drippy mustache"? he thinks. He later softens his opinion, but he dislike the fact that Perls, like Dr. Adler, is materialistic and appears to worship money. He later finds out that Perls has a progressive bone disease that is gradually destroying him.
Mr. Rappaport is a nearly blind old man Wilhelm meets at the brokerage office. He made a fortune in the chicken business, and Wilhelm hopes he will pass on some useful advice, but he is disappointed. Rappaport once met Teddy Roosevelt, and he still idolizes the man. Tamkin claims that Rappaport is a bigamist who used to maintain two separate families. Wilhelm finds that hard to believe.
Mr. Rowland is an elderly man Wilhelm meets at the brokerage office. He is a bachelor who has made money from the market almost all his life.
Rubin is an acquaintance of Wilhelm who owns the newsstand in the Hotel Gloriana. He and Wilhelm chat early in the morning, before breakfast.
Dr. Tamkin is a man in his fifties who lives at the Hotel Gloriana. He is a mysterious figure. No one is completely certain of who he really is or what he does. Wilhelm thinks he is a psychologist and wonders if he is also a hypnotist. Mr. Perls assumes he is a medical doctor. Tamkin calls himself a scientist and a healer. He claims to have patients and to treat them with unusual methods and theories. He also fancies himself as a poet and an inventor. He tells Wilhelm fantastic stories about his life and his exploits and he explains his psychological theories with great confidence, as if he is expounding upon universal truths. He says that he reads "the best of literature, science and philosophy," naming Aristotle and Freud, among others, and the "great poets."
Tamkin is also a financial speculator. He persuades Wilhelm to trust his judgment about investing in the commodities market, although his prediction that the price of lard will go up proves to be hopelessly wrong. Tamkin is also something of a conman, since he talks Wilhelm into putting up most of the money for their investment, even though they had agreed on an equal partnership. Wilhelm guesses that Tamkin may be a liar, but he cannot break free of his influence. Other characters see through Tamkin more clearly. Dr. Adler thinks he is cunning and clever, but probably a liar and possibly even crazy. In the end, when Wilhelm has lost all his money, Tamkin disappears.
Maurice Venice was the seedy, untrustworthy talent scout who promised Wilhelm as a young man that he could succeed in Hollywood as a movie star. It later turned out that Venice had little influence in Hollywood. A few years later, Wilhelm read in the newspaper that Venice had been sentenced to fifteen years in prison for running a call-girl ring.
Margaret Wilhelm is Wilhelm's wife, from whom he seeks a divorce. She expects him to support her and their two sons, even though she has a college degree and could get a job. Wilhelm feels that she has power over him and is trying to destroy him.
Tommy Wilhelm is the central character in the story. He is a big man in his mid-forties who is slovenly in his manners and does not take much trouble with his appearance. A salesman, he has recently left his job with the Rojax Corporation. He therefore has no income and is in a desperate situation. He has left his wife Margaret, but he still has to support her and their two sons. He would like to marry his girlfriend, Olive, but his wife refuses to give him a divorce.
Wilhelm feels completely isolated in his present situation. Estranged from his wife, he also has only a distant relationship with his father, Dr. Adler, even though they are now living in the same hotel in New York. His father refuses on principle to help Wilhelm financially and he is disgusted by his son's lifestyle. He visited his room in the hotel once and thought that Wilhelm "lived in worse filth than a savage." Dr. Adler refuses to ride with him in his car because it is so messy, and also because Wilhelm is such an inattentive driver.
Wilhelm feels like a drowning man. In his desperate need, he has attached himself to Dr. Tamkin, who promises to help him make money on the commodities market. Wilhelm goes along with his advice, even though he suspects Tamkin is a charlatan.
Wilhelm is in a near constant state of anxiety and agitation. He keeps taking pills in an effort to calm himself down. He feels his life is out of control and that he is heading for disaster. At one point he prays to God for a miracle that will save him.
Wilhelm has been making mistakes in life for a long time. He is the only member of his family not to complete college (although he often lies that he graduated). He dropped out because while he was in college he was persuaded by an unscrupulous talent scout, who was impressed by his good looks, that he could become a movie star in Hollywood. The scheme came to nothing, although it did result in Wilhelm changing his first name from Wilky to Tommy. But he never succeeded in becoming what he hoped Tommy would be. He does not really know who he is, and he does not feel he has the ability to change himself.