Ramban's Torah Commentaryפירוש הרמב"ן

Nachmanides embedded Kabbalah in the mainstream by dropping sealed hints — "by the way of truth..." — into the most widely studied Torah commentary ever written: the Torah as one continuous Name of God, creation from a point of potential (which moderns love comparing to singularities), the Land as the place where the Shekhinah touches ground. Esotericism smuggled into every synagogue bookshelf.