He wrote a poem in praise of limestone. He wrote a poem about Sigmund Freud. He wrote poems about cats and opera, about the minute organisms that live on human skin. He wrote an achingly beautiful love poem, a lullaby that stands among the gentlest and most forgiving poetry of the 20th century. Years after his death, when the World Trade Center towers were brought to the ground, traumatised New Yorkers faxed each other copies of a poem he had written for an earlier and greater crisis, “September 1, 1939”.