A Treatise on Mental Prayer is a classic work of spiritual guidance by the Venerable Father Louis de Ponte, S.J, a renowned Spanish mystic and theologian of the sixteenth century. Drawing from the rich tradition of Christian mysticism, de Ponte offers a comprehensive and practical manual on how to pray according to the Ignatian method of prayer, which consists of three stages: the purgative way, the illuminative way, and the unitive way. In each stage, de Ponte explains the nature, means, and obstacles of mental prayer, as well as the fruits and effects that it produces in the soul. He also provides various examples and exercises to help the reader apply the principles of mental prayer to his or her own spiritual life. This book is a condensed and updated version of the introductions to de Ponte's esteemed six volumes of Meditations, which cover the whole liturgical year and various aspects of Christian doctrine and morality. It is intended to serve as a standalone treatise that can be read independently of the Meditations, or as a companion that can enhance their understanding and practice. Whether you are a beginner or an advanced practitioner of mental prayer, you will find in this book a treasure of wisdom and inspiration that will lead you to a deeper union with God.