Will You Help Me? Handbook of Devotion to Divine Mercy
This is probably the most popular Divine Mercy book in the world having sold millions copies to date.
It teaches people about the elements of the devotion such as the Feast of Mercy, Image, Chaplet, Novena, Diary, St. Faustina and the History of Devotion. It also teaches people how to say the prayers and novena, important feast days, and the main Catholic doctrine.
Softcover, 136 pages