Betrayal is scary because it is impossible to protect yourself from it: it comes from the closest people whom we love and whom we trust. No wonder Dante in "Divine Comedy" placed traitors in the most terrible circle of hell... Betrayal as a historical phenomenon has an incredible range of forms and shades. What is considered a betrayal, can it be justified or understood? Betrayal in war and in peaceful life are two different things. In war, betrayal is "calculated" unambiguously - this is treason, aiding and going over to the side of the enemy. And in peacetime, is it possible to consider treason against the ruler of the state, who has become a tyrant? There are no unequivocal answers in this book, rather, it is an invitation to a wide public discussion. We will talk about the betrayals of genuine and imaginary, about the facets, forms and types of this phenomenon: high treason, aiding the enemy, renouncing this word and oath, fleeing to another country, issuing military secrets... We will also talk about those who were branded with treason, accused of betrayal, but did not commit such. History is a kind of textbook of morality and morality. The history of topics is important because today we know the results of certain actions and understand what they led to. The notions of decency, duty, morality, honor, loyalty and treason that guide us today have been in place for a long time, and what is considered treason today was considered treason and betrayal centuries ago.