This book throws light on the dialogue between the Orthodox theological tradition and the various religious and philosophical systems originating from both East and West. It is offered to our fellow Christians, Orthodox and non-Orthodox, so that they can follow the encounter between Orthodox theology and other philosophical and religious points of view, as well as deepening their knowledge of the Church’s traditional teaching on the inner life of spiritual vigilance. Published thirty years ago in Greek to counter the various trends coming into Greece from outside, this book, newly translated into English, is now moving in the opposite direction, travelling from Greece to the East and the West to speak to all those who long to overcome death and find eternal life. Readers will share in the dialogue between Orthodox theology and other traditions, and will deepen their awareness of the Church’s teaching on spiritual vigilance. It is now ‘time to act’ by expressing and experiencing the Orthodox tradition. This is the most potent safeguard for Christians in the times ahead. The title Time to Act signifies the urgent need for all of us to experience the Orthodox tradition for ourselves, and not just to talk and read about it. This is the most potent safeguard for Christians in the times ahead.