An English novelist and journalist, whose work contains a great deal of material influenced by and originating in Australia, Roberts came to Australia in 1877, living and working in Melbourne, the Riverina, and NSW on railroads and in the bush. He returned as a sailor to England in 1879 where he worked for a short time as civil servant. He left to travel, revisiting in the course of other travels, as demonstrated by Land-travel and Sea-faring (1891), and A Tramp's Notebook (1904) which contain chapters on the Australian experience. His first work, The Western Avenus (1887) detailed his travel experiences in America, including walking from Oregon to California (whilst reading Virgil), working in sawmills, railroads and with stock.
The Oxford Dictionary of National Biography (2004-2007) says that "critics agree that he wrote far too much and too quickly, his popularity with the average reader being acquired at the cost of quality". Roberts' first nine years of writing produced six novels, six volumes of short stories, a travel volume, and a volume of poetry. To support his family in the fifteen years of his marriage, he was responsible for another twenty novels, sixteen volumes of short stories, essays, and another travel book.
His best known work, The Private Life of Henry Maitland (1912), based on the life of George Gissing, includes references to his travels in Australia. He also wrote several plays, four volumes of poetry and a book of essays. Many of his short stories were also published in magazines such as Argosy (UK), The Strand Magazine, The Saturday Evening Post, and The London Magazine. His other themes included psychological (A Question of Time, 1895), political (The Colossus, 1899) and scientific issues. His work Malignancy and Evolution: a biological inquiry into the nature and causes of cancer (1926) was valued for its contribution to cancer research at the time and Roberts felt that he would be remembered for this, not his literary works.
After his wife's death, Roberts began his autobiography. It was still in manuscript form when seen before he died by his biographer Storm Jameson. Jameson later could not find that it was ever published, nor could she locate the manuscript.