I get curious about titles like this a lot, because 'beautiful minds' can point to different books — the most famous near-match is Sylvia Nasar's 'A Beautiful Mind', which many people mean when they ask about characters. The core person there is John Forbes Nash Jr. (the mathematician whose life the book profiles) and his wife Alicia Larde Nash, who figures prominently as companion, advocate, and the emotional center of much of the story.
Beyond those two, the narrative brings in a circle of colleagues, classmates, and family who shape Nash's life and career. If you watched the movie version titled 'A Beautiful Mind', you’ll also remember invented or dramatized figures like Charles Herman (the roommate), William Parcher (the mysterious agent), and Marcee (the little girl) — these serve cinematic purposes to dramatize Nash’s schizophrenia. The book, being a biography, leans more on real-world colleagues, mentors, and the academic/medical people around him. If you want specifics for a particular edition with full names of supporting figures, checking the book’s index or a reliable summary will nail it down faster than memory alone.