St. Alphonsus, Doctor of the Church and master spiritual guide, reveals in these timeless pages how prayer is the key to salvation and the sure weapon against the devil’s assaults. He explains why mental prayer, more than any other devotion, helps you discover hidden sins, hear God’s voice, and receive every grace you need. With practical, inspiring advice, you’ll learn how to pray with confidence, persevere through trials, and cultivate daily habits of holy reflection that anchor your soul in God’s love.