What is a person? What role do genes play in the formation of personality, and what role do the processes occurring in our brain play? Today, scientists believe that personality and intelligence are determined by the connectome, the collection of connections between neurons. Describing the human connectome is an incredibly complex task, its solution will be no less important a stage in the development of science than deciphering the genome. It is not without reason that in 2009 the US National Institutes of Health launched a special project, “The Human Connectome,” in which scientists from many countries are now participating. In his book, Sebastian Seung, a famous American scientist, professor of computational neurobiology at the Massachusetts Institute of Technology, talks about the latest results obtained in the study of the human connectome, and why we need all this.