Ewart was a Scottish author who migrated to Australia. His other works - all written under the pseudonym 'Boyd Cable' - include books on economics, shipping and military history, including for example, Doing Their Bit: War Work at Home (1916), British Battles of Destiny (1926) and A Hundred Year History of the P. & O. (1937).

A par written by Narrung and published in Smith's Weekly in 1919 provides a brief insight into Ewart and his alter ego:

Boyd Cable is not a native-born Australian. He lived here long enough to admit, when I knew him in 1911-12, that Australia was the best of lands. None of his published works have ever disclosed his real name - Ernest Ewart. A great pal of the late Samuel Locke, he was a member of a little coterie which spent many a pleasant Sunday cruising round the harbour bays. Ewart, who had seen service in South Africa, had very strong views about the menace of European militarism. There is no reason to grudge "Boyd Cable" his local success as a "best-seller." Most of his books are worth attention, and in the "hush" days of 1915-16 he gave us many secrets without straining the censorship to betrayal. Besides few people know that he was ever in Australia (5 July 1919, p.3).