The nigh omni-competent Garry Wills has a piece in the current "New York Review of Books" on the collaboration between Giuseppe Verdi and his last and greatest librettist, Arrigo Boito. The article is only available to subscribers, but it begins:
Verdi had a great advantage over Rossinis Otello (1816) in composing his own Otello (1887). It was an advantage, even, over his earlier Shakespearean opera, Macbeth (1847). Verdi had as his librettist, by the 1880s, Arrigo Boito, a highly cultured poet and musician, a man as serious about getting to the true meaning of Shakespeare as was Verdi himself.
Their collaboration produced the two stupendous Shakespearean masterpieces of Verdi's old age: Otello and Falstaff. The latter, the final operatic offspring of the eighty year old Verdi, ends famously with a cosmic fugue whose words are: "Everything in the world is a prank, and man is born a clown ... Everyone laughs at others' folly -- but the one who laughs last, laughs best!"Here is a fine performance of that final scene.