The letter is a satirical yet formal address to a sovereign, praising his longevity and favourably comparing them to historical figures who died young. The author criticises the French judicial system for its cruelty and advocates for the promotion of a young man, Talonde, who was unjustly persecuted. Additionally, the letter critiques the posthumous work of Helvétius as largely trivial, despite containing some valuable insights. The author concludes by reflecting on the political situation in Europe and returning to a simple, contemplative life.

The writer discusses receiving Helvétius’s De l’Esprit and notes that he is now relieved of the task of forwarding it. He is puzzled by the strong opposition to Helvétius, whom he sees as a philosopher advancing harmless truths, and suspects hidden enemies may have fuelled the backlash. While he disagrees with some points, he finds the work largely sound and inoffensive.