"Superstition in All Ages" is a book written by French priest and philosopher Jean Meslier in the early 18th century. The book is a critique of religion and an argument for atheism. Meslier argues that religion, particularly Christianity, is based on superstition and that its claims cannot be proven.

Meslier's book is divided into two parts. The first part examines the origins of superstition and religion, arguing that they are based on fear, ignorance, and the desire for power. Meslier claims that the belief in supernatural beings and forces is a result of humanity's inability to explain natural phenomena, and that religion is a way for those in power to control and manipulate the masses.

The second part of the book is a direct attack on Christianity. Meslier argues that the Bible is a collection of myths and legends, and that its moral teachings are inconsistent and often immoral. He also critiques the Christian concept of God, arguing that it is illogical and contradictory.

Meslier's arguments were highly controversial in his time, and he was forced to keep his atheism a secret to avoid persecution. After his death, his manuscript was discovered and published, making him one of the earliest and most influential atheist thinkers in history.