This book was born from an inner calling for us to live, deeply and in greater readiness, the guidelines and revelations transmitted to us by the spiritual Hierarchy. It contains practical and precise instructions for an intensive work of attunement with the Planetary Center of Lis. In the past, Lis was the base for important manifestations of the Mother of the World: in Lourdes (France, 1858) and in Fátima (Portugal, 1917). These were manifestations that changed the destiny of humanity. Once again we are now being called by Lis to take part in Her planetary task. Will we be willing to respond?