This book is written to enrich the knowledge of Catholics about the wonderful gift of the mercy of God for souls. Who, on dying and appearing before the Divine Tribunal of our Lord Jesus Christ, without a perfect and holy preparation, are rescued from the punishment of eternal damnation and taken to live in a state of purification or purgation. Where, after passing through a trial by fire, they have the opportunity to enter into the fullness of the eternal glory of Paradise. The first part of the book is a compilation of excerpts from the Councils, in which the existence of Purgatory is established as a dogmatic reality for the Catholic believer. The second part is a collection of testimonies of mystics and saints of the Church, who have left a valuable legacy of information on their experiences with souls in Purgatory and of their innumerable sufferings. They are useful to us as profound reflections on the responsibilities we all have in our preparation for the days we face after our death. The third part is a testimony of the author's mystical experience, which enables one to share the depth of his vision of the sufferings souls endure in Purgatory. The essential message of this book is to present the infinite Mercy of God, which continues even after our death.