Guide for the Perplexed מורה נבוכים
The Rambam's philosophical work for those loyal to Torah who also understand philosophy — and are torn between them.
The Guide was written in Arabic and is explicitly not addressed to everyone: the Rambam says he writes for a person trained in the sciences and therefore «perplexed» — unsure how to understand bodily language about God, accounts of miracles, or the reasons for the commandments.
It begins with language: «hand», «eye», «descended» are all metaphor, and belief in a corporeal Creator is called an error. Then come proofs of God's existence and unity, the argument over creation against Aristotle's eternal matter, prophecy as the highest reach of intellect and imagination, providence and suffering, and finally the reasons for the commandments, each of which, he insists, has one.
The book was revered, and also banned and burned; the controversy over it split communities in Provence and Spain.