The essay Lettre à d'Alembert sur les spectacles , first published in 1758, was written by Jean-Jacques Rousseau as a response to the essay Geneva by Jean d'Alembert which appeared in the Encyclopédie. d'Alembert proposed to establish a theatre in Geneva. Rousseau opposed the idea, arguing that the move would harm the city’s delicate social fabric.

The book is made up of six meditations, in which Descartes first discards all belief in things that are not absolutely certain, and then tries to establish what can be known for sure. He wrote the meditations as if he had meditated for six days: each meditation refers to the last one as "yesterday". The Meditations consist of the presentation of Descartes' metaphysical system in its most detailed level and in the expanding of Descartes' philosophical system, which he first introduced in the fourth part of his Discourse on Method (1637).

Emile , the greatest philosophical essay of Jean-Jacques Rousseau, is considered a masterpiece not only in educational thought but also social and political philosophy.