The author
The unnamed narrator of the story, who may or may not represent Ben Lerner. At the beginning of the novel, the author is diagnosed with aortic dilation, a heart condition that may be fatal or require dangerous surgery. This diagnosis forms the central tension of the story.
The agent
A literary agent who represents the unnamed narrator and who coordinates with a large publishing firm on his behalf.
Alex/Liza
The author's best friend since college, whose pseudonym switches between Liza and Alex throughout the novel. She is the most important character after the author, and his decisions often revolve around her needs; for example, he sells a short story in order to pay for her wisdom tooth surgery. Their relationship is very close and they have agreed to always privilege their friendship over any romantic relationships the two of them might form with others. When Alex decides to become a mother via intrauterine insemination, she chooses the author as sperm donor.
Roberto
A Hispanic elementary school student whom the author tutors after school. After taking Roberto on a field trip to a Museum of Natural Science, the author experiences deep feelings of inadequacy due to his lack of experience caring for children. A short story the author and Roberto co-authored about dinosaurs, To the Future, is included within 10:04.
Alena/Hannah
The author's sexual partner and maybe-girlfriend, whose pseudonym switches between Alena and Hannah. Alena is a talented artist who founds the "Institute for Totaled Art," an exhibit of pieces that have suffered irreparable damage and been declared a total loss by art insurers. The author ends things with her after deciding to pursue fatherhood with Alex.
Natali and Bernard
An older couple who are long-time mentors and close friends of the author. They are both incredibly well-read and prolific authors, having published more than twenty books each. The author describes them as patient, kind, and wise, and relates having spent much time in their home as a young man.
Sharon and Jon
The author's oldest friends in New York City, a couple who work at a film production company that specializes in documentaries. They introduce the author to his partner, Alena.
Diane
An New York-based acquaintance of the author whom he meets unexpectedly during his residency in Marfa, Texas. She takes him on a private tour of the Chinati Foundation and invites him to a house party where he has an unpleasant experience with ketamine.
