In 1894, after having spent her youth in Paris, Marie-Louise Castel entered the Carmel of Lisieux. She was 20 years old and was soon to become the beneficiary of the advice and friendship of her young mistress of novices: Sister Therese of the Child Jesus. She lived in the Carmel of Lisieux until her death in 1944, putting into practice in her daily life the 'little way' taught to her by her saintly novice mistress.

Her numerous recollections have been put together here by Fr. Pierre Descouvemont, well known for his studies in Theresien spirituality. The unpretentious testimony of Sr. Marie of the Trinity demonstrates very well how anyone who practices the 'spirituality of the smile' can reach heroic heights of sanctity and declare, in spite of great suffering, "No! Life is not sad!"