This is a small treatise on the Holy Spirit: in the cosmos, in humanity, in religions, in churches and in every human person, especially in the poor. This reflection on the creative Spirit, which bursts into evolution and history, seems especially justified in times like today, in which the creation of the Spirit is in danger. No wonder we are talking about a new geological era, the anthropocene one, in which the aggressive relationship of man (sapiens and demens) with the Earth threatens to eliminate all its ecosystems and, with it, human life. With theological rigor, Leonardo Boff invites us to think of the Spirit as action, movement and irruption of the new and surprising, proposing to review the classical categories of Western, traditional and conventional discourse of theology. They are new molds, within a paradigm closer to modern cosmology, and a new model of thinking about God. This model is anticipated by men and women who thought the Spirit (Hildegarda de Bingen, Joaquín de Fiore and Juliana de Norwich or, closer in time, Paul Tillich and José Comblin), and in it the pneumatized feminine occupies a special place. As the author says, "Pentecost was only the beginning," because the Spirit, who was "the first to arrive," "continues to arrive."