Percy Francis Westerman (1876 – 22 February 1959) was an English author of children's literature, with a prolific output. Many of his books are adventure stories with military and naval themes. Biography He was born in Portsmouth, England in 1876, and educated at Portsmouth Grammar School, before taking up a clerical appointment at Portsmouth Dockyard at the age of twenty. He married Florence Wager, of Portsmouth, in 1900. Always keen sailors, they spent part of their honeymoon sailing in the Solent. Their son, John F.C. Westerman, born in 1901, also wrote adventure books for boys. At the age of 70 he was reluctantly forced by a fall to leave his houseboat for dry land, but he continued writing apace. He died at the age of 82, and his last book, Mistaken Identity, was published posthumously in 1959. Writing career His writing career allegedly began with a sixpence bet made with his wife that he could write a better story than the one he was reading to his son, who was at the time ill with chickenpox. His first book for boys, A Lad of Grit, was published by Blackie and Son Limited in 1908. In the same year, Baden-Powell founded the Scouting movement, which strongly influenced many of Westerman's books – he was a particularly keen supporter of the Sea Scouts. He published a further three books in 1911, which were so successful that he gave up his Admiralty appointment that year to become a full-time author. He lived on board a houseboat – a converted Thames barge – on the River Frome at Wareham in Dorset, where he wrote the majority of his books. An early book, The Flying Submarine (published in 1912) may indicate Westerman's genre. This boys' adventure novel was about a mysterious man from a South American country. He was an inventor, who had discovered a new kind of lighter-than-air gas that he called “helia”, which was much lighter than helium or hydrogen. He used helia in many inventions, including back-packs that could help a man float in the air or fly upwards, and in the remarkable titular submarine that could, when enough helia was used, fly! Eventually he used his flying submarine to win a war between his South American country and its belligerent neighbour. It is highly likely that Westerman derived the idea for this super-weapon from Jules Verne's Terror, the speedboat, submarine, automobile,