Recently, while writing an essay on T. S. Eliot for The New York Review, I read or reread the work of many earlier critics, and was impressed most by two of them. One was Frank Kermode, who was ninety when he wrote, in 2010, one of his greatest essays, “Eliot and the Shudder,†a breathtakingly wide-ranging and sharply-focused piece about Eliot’s unique response to the common experience of shuddering. The other was a twenty-two-year-old college senior named Barack Obama, who wrote about Eliot in a letter to his girlfriend, Alexandra McNear, when she had been assigned to write a paper...