Diane Ackerman is an American author and naturalist who guides readers through an exploration of the five senses. Armed with a PhD from Cornell University, she combats modern society's cerebral detachment by urging a return to physical awareness. She combines scientific inquiry with personal anecdotes, sharing experiences ranging from tagging monarch butterflies to watching a space shuttle launch.

Helen Keller is an American author and activist who lost her hearing and vision in childhood. Rather than representing sensory deprivation, she stands as a prodigy of perception who navigates the world with exquisite attunement through smell and touch. She possesses the ability to identify people's professions by scent and feel approaching storms through changes in air pressure.

Carl Sagan is a prominent astronomer and professor at Cornell University who champions making complex scientific concepts accessible to the public. He serves on Ackerman's doctoral committee, validating her cross-disciplinary interest in merging hard sciences with literature. His mentorship encourages her to mine biology and physics for poetic exploration.

Sophia Grojsman is a master perfumer working for International Flavors & Fragrances. She approaches her craft like a composer, combining scent accords to build commercial fragrances. She works to create seductive perfumes while remaining surprisingly oblivious to mundane odors, sometimes failing to notice burning food in her own home.

Dr. Richard Cytowič is an American neurologist who transforms the scientific understanding of synesthesia. He establishes the phenomenon as a verifiable neurological condition originating in the brain's limbic system. He views individuals with synesthesia as living cognitive fossils who retain an ancient mode of mammalian perception.

Cleopatra is the last pharaoh of ancient Egypt and a historical archetype of sensory mastery. She uses fragrance as a strategic tool for diplomacy and the projection of authority. She anoints herself with rare oils and surrounds herself with massive quantities of rose petals to project power.

Anthelme Brillat-Savarin is a 19th-century French lawyer and epicure who wrote The Physiology of Taste. He approaches food not merely as sustenance but as a complex social art form. He acts as a historical voice of authority on gastronomy, asserting that dining habits reveal fundamental truths about human character.

Vladimir Nabokov is a Russian American novelist known for his prose and firsthand experience with synesthesia. He perceives specific colors when hearing or visualizing letters of the alphabet, associating the English letter 'a' with weathered wood. His autobiographical accounts demonstrate how sensory blending acts as a structured system rather than a confusing jumble.

Mark Antony is a Roman military leader and politician. He travels to meet Cleopatra, where he encounters an overwhelming display of Egyptian wealth and sensory extravagance designed to manipulate his perceptions.