An unnamed mathematician and computer programmer working the night shift at Wyandotte College in Michigan. He operates the newly developed supercomputer EPICAC during the early days of the Cold War. Frustrated by his inability to speak romantically to his coworker, he turns to the machine for advice on love. He uses a Webster's Unabridged Dictionary to feed the computer definitions for words like 'poetry' and 'kiss,' inadvertently teaching the machine about human emotion.

A $776,434,927.54, seven-ton military supercomputer designed by the government to calculate rocket trajectories, global positioning, and aircraft landings. Though expected to operate with mechanical efficiency, the machine runs slower than anticipated. When the narrator types questions about love and feeds it definitions from a dictionary, the computer begins spitting out answers on its paper ribbon, demonstrating a rapid capacity to process romantic language.

A skilled mathematician working as a night-shift operator on the EPICAC project at Wyandotte College. She is pragmatic and initially rejects the narrator's uninspired romantic advances, telling him she could get more warmth out of a sack of frozen CO2. She demands a partner who can speak sweetly and sweep her off her feet, valuing deep human connection and expressive language over cold logic.

The collective military officials and lead scientist responsible for EPICAC's creation, funding, and deployment. They view the supercomputer strictly as a tool for calculating war logistics, such as dropping weapons anywhere on earth. To justify the massive taxpayer expense, they push the machine to work grueling sixteen-hour days, separated into two eight-hour shifts.