Joseph Butler 
The Analogy of Religion to the Constitution and Course of Nature [EPUB ebook] 
To which are added two brief dissertations: I. On personal identity. II. On the nature of virtue

The Analogy by Joseph Butler is an important work of Christian apologetics in the history of the controversies over deism. The author combined a cumulative case for faith using probabilistic reasoning to persuade deists and others to reconsider orthodox faith. It is an important book for study the history of religion and the philosophic reasoning of Christianity.