O'Brian published two novels, a collection of stories and several uncollected stories under his original name, Richard Patrick Russ. His first novel, Caesar: The Life Story of a Panda-Leopard , was written at the age of 12 and published three years later in 1930. It was a critical success, with a recommendation in the New Statesman and positive reviews in publications including the New York Herald Tribune and the Saturday Review of Literature .  :50 Other stories followed, published in boys' magazines and annuals and incorporating themes of natural history and adventure, and a collection of these and other animal stories was published in 1934 under the title Beasts Royal , with illustrations by the noted artist Charles Tunnicliffe , illustrator of Tarka the Otter . Hussein: An entertainment , set in India, was published in 1938, when he was 23. It was notable for being the first book of contemporary fiction ever published by the Oxford University Press ,  :75 to whose annuals for boys he had been a regular contributor for some years. O'Brian published very little under his original name of Russ during World War II, and nothing after 1940. His change of surname in 1945 necessarily meant abandoning the literary reputation he had built up as R. P. Russ.