The Way to Santiago (1941) is a heady hybrid of spy thriller, murder mystery, gun-toting adventure and sleek noir, playing out against the dusty landscapes of South America in the immediate aftermath of the Spanish civil war and the start of the second world war.

It follows the hapless agency writer, Englishman Jimmy Lamson, as he attempts to find the murderer of a fellow press man, hoping to find his own journalistic integrity along the way. The novel rattles through a kaleidoscopic array of Latin American vistas – sinister cantinas, crude railside shacks, glitzy palaces and dirt roads – all populated with characters you might find congregating on a Hollywood backlot: sad, red-lipped beauties, itchy-fingered assassins and clipped English gentlemen.

The novel was written by Oxford-educated author and Hollywood scriptwriter Arthur Calder-Marshall, based on his own time traveling through the region on a six-week break from his contract with MGM. It was then picked up by RKO’s new young star director, Orson Welles, who adapted the material for a film that was never made. And in a Hollywood-worthy twist, Mank – David Fincher’s new film about Welles and his fractious relationship with fellow screenwriter Herman J Mankiewicz – stars Calder-Marshall’s grandson, Tom Burke, in the role of Welles.

The novel rattles through a kaleidoscopic array of Latin American vistas all populated with characters you might find congregating on a Hollywood backlot.

“I did know about the connection when I took on the role, but through Wikipedia, rather than my grandfather,” Burke says. “He never mentioned it to me and it wasn’t a story I grew up on.”

There was no lifelong friendship between the novelist and the director, perhaps over creative differences; Welles’s failed adaptation is delightfully and typically egomaniacal, shrinking one of the novel’s characters to a darkened plot twist and replacing another with a character to be played by Welles himself. Calder-Marshall’s complex players are all but blown to dust by the director’s vision, but it remains an invaluable resource for Welles scholars – betraying his indefatigable vanity and intense narrative control over the stories he chose to tell, both of which lie at the heart of Mank.

Calder-Marshall’s memoir, best if read alongside Evelyn Waugh’s Vile Bodies.

Calder-Marshall would have fitted perfectly into any frame of Welles’s rejected film. Broodingly handsome, the author sat comfortably at the center of a literary web for much of the 20th century. His name surfaced repeatedly in letters and biographies of well-heeled, fashionable and famous men; at Oxford, his coterie included Stephen Spender, John Betjeman and Isaiah Berlin, to whom he passed on the editorship of influential undergraduate magazine The Outlook.

It was Calder-Marshall who Alec Waugh contacted to keep an eye on his difficult younger brother Evelyn during his visit to Mexico in 1940. It was Calder-Marshall who Julian Maclaren-Ross contacted while looking for work after the war. And it was Calder-Marshall who was sourced by MGM, alongside his glamorous Garboesque wife Ara, to write golden hits for Hollywood greats, until both the monotony of Los Angeles and the war forced the elegant couple to flee the town “where people looked as beautiful as the food but proved as tasteless”.

Despite this fortuitous escape, Tinseltown continued to pursue the Calder-Marshalls, with British star James Mason sourcing the writer’s later novel, Occasion of Glory, for his directing debut. Once again, the project never materialized.

It was Calder-Marshall who Alec Waugh contacted to keep an eye on his difficult younger brother Evelyn during his visit to Mexico in 1940.

Optioned work and near literary stardom were constants of Calder-Marshall’s life and career. About Levy, one of his early novels, earned a glittering review in The New York Times, which heralded its “remarkable quality”. Publisher Jonathan Cape snapped him up for a six-novel deal and the dashing Arthur and Ara were regular fixtures in the drawing rooms of Bloomsbury.

Calder-Marshall and his wife, Ara. MGM hired the couple to write hits for Hollywood greats.

Yet somehow the author remains on the periphery of renown, slipping between the mainstream and the obscure. His peculiar roster of subject matter hasn’t helped. His critically acclaimed novels were largely thrillers, but his most famous book was a children’s story, The Fair to Middling. He also completed biographies of Victorian sexologist Havelock Ellis, the ethnographic film-maker Robert Flaherty, and Anglican Benedictine monk Joseph Leycester Lyne.

His own memoir, The Magic of My Youth, does little to solve the mystery of Calder-Marshall, coded as it is in a dizzying and fantastical tale about a young Oxford student in search of occultist Aleister Crowley, a wanton influence on the writer’s formative years. It is a lavish and delirious read for anyone interested in experiencing fashionable Bloomsbury in the 1920s, the perfect complement to Evelyn Waugh’s Vile Bodies, but, as a memoir, it keeps Calder-Marshall’s own life securely under wraps.

Thankfully, a later and meticulously detailed autobiography was rattled off secretly and remains in the private archives of his daughter, actor Anna Calder-Marshall. This deeply moving and darkly funny manuscript details the life of a gifted author brushing shoulders with fame and the fallible characters it consumed. Perhaps one day it will be published – then, the real Calder-Marshall can finally step out of the shadows.