A collection of previously unreleased writings by Mother Teresa will be published in August, weeks before the late Nobel Peace Prize winner is to be canonised. A Call to Mercy: Hearts to Love, Hands to Serve will be published by Image, an imprint of the Crown Publishing Group, on August 16. The material in the book focuses on mercy and compassion. It was compiled by the postulator of the Cause of beatification and canonisation of Mother Teresa and director of the Mother Teresa Centre, Fr Brian Kolodiejchuk. Pope Francis will declare Blessed Teresa of Calcutta a saint on September 4, at the conclusion of the Year of Mercy jubilee. Hundreds of Missionaries of Charity, the religious order founded by Mother Teresa, are expected to be in Rome for her canonisation. Fr Kolodiejchuk previously edited Mother Teresa: Come Be My Light – The Private Writings of the Saint of Calcutta, pub­lished in 2007. The book dis­cussed the secret vow she made early in her vocation, when she promised not to refuse God anything on pain of mortal sin. Blessed Mother Teresa suffered dark periods in her inner life when she felt that God had abandoned her. Her vow to God “was one of the pillars that kept her going through the trials of the darkness”, Fr Kolodiejchuk said when the previous book was published. “Because of her certainty of her call and this vow, in one of the letters she says, ‘I was at the point of breaking and then I remembered the vow, and that picked me up,’ ” he said. Shortly after Mother Teresa’s death in 1997, aged 87, St John Paul II waived the usual five-year waiting period and allowed the opening of the process to canonisation.