A bestselling international literary sensation about whether a "prime number" can ever truly connect with someone else. A prime number can only be divided by itself or by one—it never truly fits with another. Alice and Mattia, both "primes," are misfits who seem destined to be alone. Haunted by childhood tragedies that mark their lives, they cannot reach out to anyone else. When Alice and Mattia meet as teenagers, they recognize in each other a kindred, damaged spirit. But the mathematically gifted Mattia accepts a research position that takes him thousands of miles away, and the two are forced to separate. Then a chance occurrence reunites them and forces a lifetime of concealed emotion to the surface. Like Mark Haddon's The Curious Incident of the Dog in the Night-Time, this is a stunning meditation on loneliness, love, and the weight of childhood experience that is set to become a universal classic.