Isaac (Fernando) Cardoso was a Jewish physician, philosopher, and polemic writer.

Isaac Casaubon was a classical scholar and philologist, first in France and then later in England.

Isaäc da Costa (14 January 1798 – 28 April 1860) was a Jewish Dutch poet.

Isaac Daniel Hooson, or I. D. Hooson as he was commonly known, was a Welsh solicitor and poet.

Isaac de Benserade (French: [bɛ̃.sʁad]; baptized 5 November 1613 – 10 October 1691) was a French poet and playwright.

Isaac Deutscher was a Polish Marxist writer, journalist and political activist who moved to the United Kingdom before the outbreak of World War II. He is best known as a biographer of Leon Trotsky and Joseph Stalin and as a commentator on Soviet affairs. His three-volume biography of Trotsky was highly influential among the British New Left in the 1960s and 1970s.

Isaac D'Israeli was a British writer, scholar and the father of British Prime Minister Benjamin Disraeli. He is best known for his essays and his associations with other men of letters.

Isaac Dov Berkowitz, was a Hebrew and Yiddish author and translator.

Isaac Erter was a Polish-Jewish satirist and poet of the Galician Haskalah. His Hebrew prose has been compared to that of writers Heinrich Heine and Ludwig Börne.

Isaac Ferris (1798-1873) was the third President of New York University.