John Heron is recruited by psychologist Stella Cranach for a series of experiments. His brain is connected to MEQMAT, the supercomputer that runs New City, and he is placed in what seems to be a vivid simulation of life in Alexandreia under the reign of Cleopatra. He inhabits the role of rhetoric teacher Nikias Rhodios and is accompanied by Charmion, a version of Stella who works as a lady-in-waiting for Cleopatra.
The Schizogenic Man contains examples of:
- Brain/Computer Interface: Heron's brain is connected to MEQMAT via electrodes.
- Career-Ending Injury: Heron and his first wife Teofila worked for six months on a space station, which was Heron's dream. But then he broke his foot (the same one he breaks years later at the warehouse), and by the time he recovered, the program he worked in had ended.
- Divided States of America: America has fragmented into several small countries, including New City, Tropicana, Texas, and the Middle. Texas eventually declares war on Tropicana, causing refugees to pour into New City. When the war turns nuclear, New City is destroyed, and MEQMAT with it. MEQMAT unsuccessfully tries to find a timeline where the war doesn't happen.
- Fascists' Bed Time: The people of New City think of their home as an island of freedom surrounded by oppressive religious states, but New City is pretty tyrannical in its own right, with laws including a strict curfew.
- King Incognito: When Heron first meets Cleopatra, she's wandering the slums of Alexandreia with a small entourage, disguised as a prostitute.
- Mental Time Travel: When Heron is placed in Nikias' mind, he has access to all his memories and knowledge, but acts fully under his own power. This is because Nikias has a weak personality - later, when Heron is placed in the mind of the clerk Diomedes, he has trouble exerting his will over him.
- The Multiverse: Every time Heron goes back in time, his mind jumps from one timeline to another. He can only travel to timelines where some version of himself exists, so even when he makes major changes like saving Cleopatra's son Kaisarion, he comes back to find the world relatively unchanged.
- Recruited from the Gutter: Charmion's backstory. She was an ordinary palace slave until Cleopatra took a liking to her. Now she's the most trusted servant of Cleopatra, to whom she is highly loyal.
- Self-Harm: At the beginning of the book, Heron breaks his foot in an accident at the warehouse where he works. He's given two weeks off work. Heron hates his job, so he kicks the wall with his injured foot until it's broken so severely that he gets a month off work and a year-long reclassification to Strictly Non-Strenuous. It's during his month off that the experiments begin.
- This Is Reality: Cleopatra tells Heron, "Only in poetry or stage plays are queens allowed to rest on their majesty."
- Well-Intentioned Extremist: When Heron was a young man, he and his friend Jemmy assassinated three warmongering Texan politicians. It turns out that while he was doing this, his mind was inhabited by the time traveler Grishka as part of MEQMAT's plan to avoid nuclear war with Texas. It didn't have the outcomes they were hoping for - the more liberal politicians who took the victims' place turned out to be weak and ineffectual, and unable to cause any change. By the present day, the government of Texas is more aggressive than ever.
- Your Makeup Is Running: Cleopatra listens to Charmion play a sad song on the lyre while she whispers the names of former lovers who have died. She sheds a tear, which trails a line of kohl down her cheek.
