"De Profundis" is a long reflective letter written by Oscar Wilde during his imprisonment in Reading Gaol. It is directed towards his former lover, Lord Alfred Douglas, blaming him for Wilde's downfall and imprisonment due to his recklessness, vanity, and quest for immediate pleasure. The book also delves deeply into Wilde's thoughts on arts, spirituality, suffering, and his profound realization of life's meaning and his role in it.