Jack Hamilton
Hamilton is the protagonist of the novel. He has recently been dismissed from his job at California Maintenance Labs not because of his own fault but because the company's chief security officer, Charles McFeyffe, has brought to the attention of the company the left-wing leanings of Hamilton's wife. Because this is a time of McCarthyism and a general fear of communism, Hamilton is terminated from his post.
Hamilton experiences all of the alternate realities that the other tour group members experience after being hit by the collapsing walkway. He travels to Heaven with his nemesis, McFeyffe, where he sees the eye of God, and it is he who realizes that they are actually living inside the mind of Arthur Sylvester. Hamilton seems to be the most practical-minded member of the group and all of his actions are designed to enable them to return to their own reality as soon as possible. He is never content to merely enjoy the alternate universes that they are traveling through or to accept that they will not return to their own reality again. Therefore, he feels that if they are trapped inside the mind of another person, rendering them unconscious should therefore be the key to freedom.
After returning to the real world, Hamilton teams up with Bill Laws to form a company that wants to advance sterephonic technology.
Marsha Hamilton
Although not a member of the tour group, Marsha is important to the story because her inclusion explains why Jack is currently on the tour and why he has been fired from his job. Ir is believe that she is either a communist or a sympathizer. However, one of the alternate realities reveals Marsha to have no such leanings, and it becomes clear that she is merely the scapegoat created by the real leftist, Charles McFeyffe.
Charles McFeyffe
The chief security officer of the California Maintenance Labs appears to be a trustworthy and reliable person, at least to his bosses, who take him at his word that Hamilton's wife is a communist, and follow his recommendations to terminate Jack as an employee. However, it is revealed at the end of the book that he is actually a communist "plant" himself, and that he is using his position as the security chief of the company to further the goals of the Communist Party. He has offered up Marsha Hamilton as the left-leaning operative that they are trying to protect themselves from as a smokescreen for his own political objectives. However, since the evidence of this was revealed whilst the tour group were in an alternative reality, the charges cannot be proven and are therefore dismissed.
Bill Laws
Laws is an African-American scientist with a PhD in Physics, but he is employed as a mere tour guide by California Maintenance Labs to show people around the Belmont Bevatron. This fact implies a racism in the company as evidenced by its refusal to employ him according to his educational level. Laws and Hamilton find they have much in common and at the end of the novel begin a business together developing the future of stereophonic technologies.
Joan Reiss
Pathologically paranoid, Reiss is a middle aged woman in whose mind the tour group exist momentarily. The universe in which they find themselves is constructed solely from her paranoid delusions.
Edith and David Pritchet
The final reality in which the tour group reside is the world as it would be if it was governed by Edith Pritchet. An older, maternal woman with a Victorian ability to censure almost anything that gives anybody enjoyment, she is taking the tour with her son, David. The second universe experienced by the group sees everything that Edith disapproves of - which is most things - abolished.
