Christopher Smart (1722–1771) was a madman, a genius, a Christian poet, and a mystic of small things. At his worst, he would rage against his father-in-law (with, it must be admitted, some justification). At his best he could convey the delicate mysticism that is not pantheism but nonetheless sees the world as infused with grace, a hunger for redemption, and the constant interaction of creatures and creator. His most referenced poem, “Jubilate Agno,” opens with a long description of his cat’s relation to God — hilariously exaggerated, sharply observed, and mystically suffused with the sense that to exist is to be caught up in the great narrative of creation.