Dr. Leistiko is a professor of psychology at Stanford University who studies the impact of culture on suicide. Ruth finds his website when she is looking for Nao and her family online, and she finds an excerpt from a letter on Leistiko’s website that she suspects might be written Haruki. It turns out that Leistiko and Haruki were friends when Haruki used to live in California. While Haruki is usually shown through Nao’s point of view in the novel, Leistiko’s emails to Ruth show different aspects of Haruki’s character. While Nao sees her father as a loving but defeated man, Leistiko’s emails reveal that Haruki is a brilliant programmer and an ethical person.