Harold Edward Leslie Mellersh (1897–1980) was a British writer, primarily of text books. He was born in Harlesdon, London, and died in Stogumber, Somerset. He was married in Battersea, London in 1921, and had 3 daughters and 1 son.

Mellersh had published about 25 books, including 3 novels in 1926 – 1931, and an autobiography about his experience of World War I. The autobiography, Schoolboy into War is an account of his recruitment at the age of 18, directly from school as an officer in the British Army. He was commissioned into the East Lancashire Regiment in 1915, served on the Western Front, and was wounded three times (once each in 1916, 1917 & 1918). His family then lived in St Alban's, Hertfordshire, where they took in 2 refugees from Belgium, a mother and her young daughter, with the surname of Louwage.

Quote: "I and my like entered the war expecting an heroic adventure and believing implicitly in the rightness of our cause [sounds like Cather's hero Claude]; we ended greatly disillusioned as to the nature of the adventure, but still believing that our cause was right and we had not fought in vain."

A later non-fiction book was about "Fitzroy of the Beagle," because a midshipman aboard Darwin's famous voyage round the world had the same surname of Mellersh (though no direct genealogical connection could be made).

In 1921 Mellersh joined the Inland Revenue as a tax inspector.