Last month, when I was suffering from a vertigo and unable to read for more than a few seconds at a time, my constant companion was the incomparable Ella Fitzgerald, and especially her four great Songbooks: Gershwin, Ellington, Cole Porter, and Rodgers & Hart. Collectively they constitute, I believe, one of the great achievements of 20th-century American art. Ella recorded other “songbook” albums, including an Irving Berlin one, but these four are the masterpieces. And I might note that t...