The book’s final chapter opens with Amos receiving a MacArthur “genius” grant. After receiving the award, a friend of Amos’s recalled, “He was pissed. He said, ‘What are these people thinking? How can they give a prize to just one of a winning pair? Do they not realize they are dealing the collaboration a death blow?’” (313). This trend of organizations remembering and recognizing Amos but forgetting or leaving out Danny continued, and Danny inevitably noticed. He admitted to his frustration, saying, “You get fed up with not being invited to the same conferences, even when you would not want to go” (316).

Their final work together was not one last stroke of genius, one last amendment or addendum to their research on heuristics or subjective probability. Instead, at Amos’s insistent request, it was a letter sent in response to their fiercest critic, a German psychologist named Gerd Gigerenzer. Amos wanted to destroy Gigerenzer. It was during this back-and-forth that Danny finally had enough, especially after Amos refused to put Danny’s name forth for the National Academy of Sciences, to which Amos had already belonged for years. Danny walked away from the friendship, a de facto divorce, ending a productive collaboration that had lasted more than a decade.