The book True Devotion to Mary was written by St. Louis-Marie Grignion de Montfort in 1712.
The manuscript remained practically unknown for more than a century, and it was discovered by chance in 1842, at the Motherhouse of the Missionaries of the Company of Mary at St. Laurent-sur-Sèvre, France. There have been stories circulating of a prohesy by St Louis that the book was so much hated by the devil that he would attempt to keep it hidden from others for a 100 years. The discovery of the book and its publication led to an immediate rise in devotion to the Blessed Virgin Mary and the repentance and conversion of many souls.
This timeless classic is a must-read and a must-have book for every Catholic bookshelf.