Book excerpt: We have the right and the duty to defend ourselves from invasion or injustice, but we must do so intelligently, effectively and ethically. Wars are a Crime Against Humanity. Therefore, learning to defend ourselves, as the book explains, is a way forward for the survival of the human species. Pepe Beunza As the author says, if oppression and injustice are maintained, it is because we collaborate with them. For this reason, the book provides people with tools so that, in the event of conflict, they can maintain their dignity and work for Peace, so that waging war does favour those who have provoked it. Llúcia Oliva Information and proposals are presented, aimed at achieving the creation of a nonviolent force for self-defense, in a new security paradigm. An unheard-of utopia, but not impossible. Xavier Masllorens In adaptation to this world of social networks, the present publication breaks down in detail everything that lies behind a civilian system of nonviolent defense in 100 short messages. Thais Bonilla It is a highly valuable document to face the convulsive times we are living in, and it helps a lot, with tools and arguments, to create a base for a peaceful and democratic movement. The text that Martí Olivella proposes to us, points out a way that is as necessary, as it is useful. Raül Romeva