Owen Dudley Edwards has failed to uncover the story of this strange writer who produced over 120 books in twelve years before dying young at 48 years old. He refers only to Marise Flies South (1944) although he does talk about the 'impressively professional series' . The biography/bibliography is Among Her Own People: Lives and Literature of Eileen Marsh, Jack Heming and Bracebridge Heming by Eric Bates (Bulman Lee Publishing, Ashford [firstname.lastname@example.org], ISBN 0-9551014-0-9. I have a collection of about 60 titles.
Eileen Marsh wrote under many names often combining her real names Dorothy Eileen Heming (nee Marsh) or using other family names. She published 7 titles in 1936, 4 as Eileen Marsh, and one each of Dorothy Carter, Martin Kent and D.E. Marsh. Of the twelve titles in 1937, 5 were by Eileen Marsh, 2 by D.E. Marsh, and one each by James Cahill, Guy Demster, Martin Kent, Elizabeth Rogers and E M Shard. 1938 added John Annerley, D.E. Heming, Dempster Heming to two Martin Kents, and one D.E Marsh, Eileen Marsh and Elizabeth Rogers. . Altogether there were 26 by Eileen Marsh, 14 by Dorothy Carter, 9 by Elizabeth Rogers, 8 by Guy Dempster (bloodthirsty boys' war stuff) , 6 by Martin Kent, 6 by D.E. Marsh, and smaller numbers for the rest. She also wrote adult novels, and Sunday School prizes for Lutterworth, using Eileen Heming, Dorothy Marsh, James Cahill, Rupert Jardine, Jane Rogers and Mary St. Helier. This was quite a varied output for girls, boys and adults. She specialised in writing about flying and war adventure, and set them in England, Canada, Africa, USA and even up the Himalayas. She herself could not fly (though she had flying contacts and had a few flying lessons after writing several books; and had never visited many of these places: she wrote at home bringing up five children. Her husband also wrote, but was interrupted by the war. He used her pseudonyms from time to time after her death.
Eileen Marsh wrote her life story as fiction, in A Woman's Life where she describes a woman and husband writers who were advised to write aeroplane stories as the modern thing. Her routine was three hours writings while the children were in school, or 5000 words per day. The first books, under the signature D.E. Marsh were for boys, her Eileen Marsh signature starting with her girl flier books, of which Jonquil is the easiest to find. She states her payment per book as £50. In all, she wrote 120 books between 1935 and 1948, under 16 names, for girls, boys and adults.
ODE notes (p.229 fn29) that Dorothy Carter had no books after 1948. In fact The Cruise of the Golden Dawn was published by Latimer House in 1949, just posthumously. North for Treasure came in 1961, published by Lutterworth about the Canadian gold rush. Five genuine Dorothy Carters had been with Lutterworth, the rest with Collins (the first, Flying Dawn, was with A&C Black in 1935. An open question is whether the 1961 title was wholly written by husband Jack, or is a reworking of an unfinished manuscript. A number of pre-war titles were set in Canada, but I have not found any trace in copyright libraries of an earlier version of North of Treasure. Also set in Canada, Ted of the Mounties used the name Eileen Heming (1955) - again was this Jack, or is it a reprint of and earlier genuine title? Eric Bates gives their authorship to Jack; I am open to the possibility that they were written in Canada in the 1930s - Elizabeth Rogers' On Wings and Skis, set in Canada, was in 1939.