"Coplas por la muerte de su padre" is a collection of elegiac verses written in memory of the author's father. The poems explore themes of mortality, the fleeting nature of life, and the inevitability of death. The author uses his personal grief as a platform to delve into philosophical reflections, ultimately presenting a stoic acceptance of death as a natural part of life. The work is widely regarded as one of the greatest achievements in Spanish poetry.

The book explores the profound spiritual journey of the soul as it undergoes a period of deep inner turmoil and purification, often referred to as the "dark night." This transformative experience, marked by feelings of desolation and abandonment, ultimately leads to a closer union with the divine. Through this intense process, the soul is stripped of its attachments and ego, emerging with a deeper, more authentic relationship with God. The work provides both a poetic and theological framework for understanding this challenging yet essential phase of spiritual development.

"Hymns to the Night" is a collection of six prose hymns that delve into the profound depths of night as a metaphor for the mystical and the transcendent. The work reflects on the dichotomy between darkness and light, with the night representing a sanctuary from the rationality and order of the day. It is a deeply romantic text that celebrates the beauty and solace found in the nocturnal realm, where the spiritual and the eternal are felt more acutely. The hymns are a blend of personal longing, philosophical contemplation, and spiritual quest, expressing a yearning for the infinite and the reunion with a lost beloved, symbolizing the soul's journey towards oneness with the divine.