A Treatise on Toleration and Other Essays Book

An impassioned plea for religious tolerance by Voltaire, triggered by the execution of Jean Calas in Toulouse.
Jean Calas was a Protestant merchant in Toulouse who was sentenced to death for the murder of his son. All the evidence pointed to suicide by hanging and Calas was a frail man who would not have had the strength to murder his son in this way. Calas was sentenced to be broken at the wheel, a particularly brutal form of execution. Voltaire heard about the cause and took up the cause for a posthumous pardon and compensation for the remaining family. It was a long battle and this treatise is part of the campaign.
The treatise is a run through of recent French history in relation to tolerance and especially the persecution of the Huguenots. Voltaire proceeds to look at Christian history, the early Church Fathers, the Bible, other religions and the ancient Greeks and Romans. Throughout Voltaire emphasises his own Christian credentials as a good Catholic; but his arguments, caustic wit and sheer scepticism point to him being distant from religious belief, or as much as he could be at the time. He is essentially a Deist.
Voltaire treats the reader to an entertaining run through some of the battier beliefs of the early church and examines the persecution by the Romans to show that this has been exaggerated and most of the time the church went out of its way to attract persecution. He also contrasts the bloodthirstiness of the Old Testament with the more tolerant approach of the New Testament. Of course Voltaire continues to make the point that if you are right you don't need to persecute, just persuade. He also shows a preference for Eastern religions as opposed to the Religions of the Book (Judaism, Christianity and Islam).
This is a very humane book, baffled by the inhumanity of the Church and arguing for the toleration and free thought. It feels very modern.