Well-known as a naturalist and journalist, Barrett was the author of more than one hundred books, whose topics include Indigenous Australians, natural history, travel, history, social life and customs. He was a member of the literary staff of the Melbourne Herald for thirty-three years from 1906. conducting the Wild Nature Notes page, the Australian Boys' Page and the Camp Fire in the Weekly Times. He contributed the column 'From my Inglenook: Gossip on Nature, Men and Books' to All About Books (1929) and edited The Victorian Naturalist (1925-40), Pals (1920-27) and some Australian First World War journals. Under the pseudonym 'Malorus' he contributed stories to Pals.
A serial 'The Wide Horizon' was published in Everylady's Journal. Barrett was awarded the Australian Natural History Medallio in 1953.
During World War I Barrett served in the Middle East with the Australian Camel Brigade Field Ambulance. During this period he edited the service magazine, the Kia-ora Coo-ee, for which he wrote a regular 'Nature Studies in Palestine' column along with occasional travel/historical articles.
