Isabel Ecclestone Mackay was a Canadian novelist and poet.

Isabel Florence Hapgood was an American ecumenist, writer and translator, especially of Russian and French texts.

Isabel Egenton Ostrander (1883–1924) was a mystery writer of the early twentieth century who used her own name and the pseudonyms Robert Orr Chipperfield, David Fox, and Douglas Grant. Christopher B. Booth is sometimes (falsely) credited as a pseudonym of hers.

Isabella Lucy Bishop was an English explorer, writer, photographer and naturalist. Alongside fellow Englishwoman Fanny Jane Butler, she founded the John Bishop Memorial Hospital in Srinagar in modern-day Kashmir. She was also the first woman to be elected as a fellow of the Royal Geographical Society.

Isabella Valancy Crawford was an Irish-born Canadian writer and poet. She was one of the first Canadians to make a living as a freelance writer.

Israel Abrahams, MA (honoris causa) was one of the most distinguished Jewish scholars of his generation. He wrote a number of classics on Judaism, most notably, Jewish Life in the Middle Ages (1896).

Israel Zangwill was a British author at the forefront of cultural Zionism during the 19th century, and was a close associate of Theodor Herzl. He later rejected the search for a Jewish homeland in Palestine and became the prime thinker behind the territorial movement.

Ivan Sergeyevich Turgenev was a Russian novelist, short story writer, poet, playwright, translator and popularizer of Russian literature in the West.

Ivor Bertie Gurney was an English poet and composer, particularly of songs. He was born and raised in Gloucester. He suffered from bipolar disorder through much of his life and spent his last 15 years in psychiatric hospitals. Critical evaluation of Gurney has been complicated by this, and also by the need to assess both his poetry and his music. Gurney himself thought of music as his true vocation: "The brighter visions brought music; the fainter verse".

Izaak Walton was an English writer. Best known as the author of The Compleat Angler, he also wrote a number of short biographies including one of his friend John Donne. They have been collected under the title of Walton's Lives.