Henry attributed his love for nature which characterized his entire existence to the influence of his mother, who was of Irish origin but had spent her childhood until the age of twelve in the wildest and most wooded regions of Canada.

It was not a joyful experience; in the autobiographical Men and Mice he wrote about the fact that his noisy and rough companions abused him physically and mentally, making him feel like "a little [King] Arthur in a cage of baboons."

Years later, Stacpoole retold this story in The Man Who Lost Himself (1918); a penniless American who impersonates his rich lookalike in England; and this time it was a commercial success.

(1896), is set during the Franco-Prussian War and deals with an ambiguous relationship between a French boy and his look-alike psychic double, in the form of a Prussian officer; all through a story of "family curses" from which it appears that the young Frenchman may be a parricide.

By the early 1900s, Stacpoole had become a permanent professional writer; in an interview, he claimed that he wrote 2000 words a day and that his main sources of inspiration were Edgar Allan Poe, Victor Hugo, Eugène Sue, and Robert Louis Stevenson.

He would be spared the "storm of success" for another seven years, during which time he published seven books, including a collection of children's stories and two novels in collaboration with his friend William Alexander Bryce.

Public success came, however, in 1905 with a comic-romantic novel, Fanny Lambert, and in 1907 with a sea adventure, Crimson Azaleas; in the latter two rude sailors adopt a Japanese orphan.

Stacpoole's greatest commercial success came in 1908 with The Blue Lagoon, which was reprinted at least twenty-four times in thirteen years, and from which films were released in 1923, now lost, then 1949 and 1980.

In Stacpoole's gender-reversal tradition, the Lestranges call the child Hannah and live happily ever after until they are unexpectedly expelled from their tropical Eden.

This genre became popular during the Edwardian era, thanks to the success of books such as The Wonderful Wizard of Oz by L. Frank Baum, Peter Pan by J. M. Barrie, and The Blue Bird by Maurice Maeterlinck.

Although Stacpoole initially had no intention of writing sequels, he eventually authored two additional books: The Garden of God (1923) and The Gates of Morning (1925).

In August 1920, the theatrical adaptation of The Blue Lagoon, written by Norman MacOwan and Charlton Mann, premiered at the Prince of Wales Theatre.

A significant hurdle that the production team had to overcome was a rights dispute with the original publisher, T. Fisher Unwin, which caused a lengthy delay of 12 years from the novel's release to the debut of the stage adaptation.

Despite this setback, the play eventually made its way to the stage, where it proved to be a smash hit, delighting audiences with its captivating plot and enchanting characters.

Stacpoole's written works explored diverse settings, encompassing ancient Athens, Iceland, the Greek islands, and France, among others.

Due to his deep love and appreciation for nature, he established the Penguin Club, which was dedicated to protecting seabirds from the harmful effects of oil.