Aron Iosifovich Katsenelinboigen was a founder of predispositioning theory, a subject in decision theory and systems theory that models development in the context of uncertainty.

Aron Nimzowitsch was a Latvian born-Danish chess player and writer. In the late 1920s, Nimzowitsch was one of the best chess players in the world. He was the foremost figure amongst the hypermoderns and wrote a very influential book on chess theory: My System (1925–1927). Nimzowitsch's seminal work Chess Praxis, originally published in German in 1929, was purchased by a pre-teen and future World Champion Tigran Petrosian and was to have a great influence on his development as a chess player.

Aron Pumnul was a Romanian philologist and teacher as well as a national and revolutionary activist in Transylvania and later in Bukovina.

Aron Lee Ralston is an American mountaineer, mechanical engineer, and motivational speaker, known for surviving a canyoneering accident by cutting off part of his own right arm.

Aron Vergelis was a Soviet poet and Jewish journalist who wrote in Yiddish.

Arpiar Arpiarian was an influential 19th-century Armenian writer, the pioneer of realism in Armenian literature and a political activist.

Arria Sargent Huntington was the author of Under a Colonial Roof-Tree: Fireside Chronicles of Early New England which details daily life and family stories from early days of Hadley, Massachusetts.

Arrian of Nicomedia was a Greek historian, public servant, military commander, and philosopher of the Roman period.

Arrigo Boito was an Italian librettist, composer, poet and critic whose only completed opera was Mefistofele. Among the operas for which he wrote the libretti are Giuseppe Verdi's monumental last two operas Otello and Falstaff as well as Amilcare Ponchielli's La Gioconda.

Arrigo Petacco was an Italian writer, historian and journalist.