Keable's novels won him immense international popularity and intense controversy. His novels were equated with Mrs Humphry Ward's
Robert Elsmere, a similarly scandalous tale of religious doubt among the clergy published 40 years earlier: H.D.A. Major, editor of the
Modern Churchman magazine, made this comparison with respect to Keable's
Peradventure, noting "It is slighter, but it has need to be. The twentieth century novel reader is intellectually and morally lighter than the nineteenth." Reporting his death, the Melbourne
Argus attributed the best-selling popularity of Keable's novels to the licentiousness of their contents: "they have no literary value". His former college acquaintance James later wrote that "his friends sought to dissuade him from publication. The transition from the beautiful book on
The Loneliness of Christ (1914) — of his Central African period — to
Simon Called Peter (1921) came as a great shock to all who had known and loved him in earlier days." Where Rosemary Grimble calls Keable's novels "splendidly erotic", a
Birmingham News correspondent in Birmingham, Alabama, accused Keable of "fashioning abnormalities". Other critics called his success "undeserved" and attributed it to prurience on the part of his readers. Reviewers also suggested that the contrast between Keable's ecclesiastical background and the frank, often sexual, content of his novels attracted curiosity in itself. A
Time columnist, "J.F.", expressed the fascination of this disconnect overtly, responding to a piece titled "The censorship of thought" that Keable had contributed to a 1922 volume,
Nonsenseorship (
sic), after
Simon Called Peter's publication had made him notorious. "Surely, here is a modern personality worth the study of the psychologists," J.F. wrote, noting the romance of Keable's unusual circumstances: "From a quiet English clergyman to the author of a sensational best-seller who has taken up his permanent residence in the South Seas seems a long jump." In person, he said, Keable was the antithesis of his novels' striking directness:
He does not impress one as a radical gentleman. There is nothing to suggest the resigned clergyman, author of books marked by their sex frankness and melodrama. In fact, his scholarly bearing and gentleness mark him rather as the country curate, who should be acting as a character in a novel by May Sinclair and passing out crumpets to maiden ladies in a decorous drawing-room instead of writing of Tahitian damsels as he has done in his new novel, Numerous Treasure.
It was for
Simon Called Peter, a tale of a wartime romance between an English priest and a Red Cross nurse, that Keable acquired most of his notoriety. As well as its bestselling print editions, the story was adapted as a stage play by Jules Eckert Goodman and Edward Knoblock in 1924. The show enjoyed popular success in Chicago before moving on to New York.
A great deal of media coverage of
Simon Called Peter concerned its involvement in a prominent United States court case, over the double murder in New Brunswick, New Jersey of Edward Wheeler Hall, a rector, and Elenor Mills, a married member of his congregation, with whom he had been conducting an affair. During their courtship Hall had presented Mills with copies of
Simon Called Peter, which also featured a romance between a priest and a woman, and
The Mother of All Living. John Sumner, the secretary of the Society for the Suppression of Vice, seized upon this fact and tried to have the books' American publisher arrested. He claimed that
Simon Called Peter could be used to corrupt and seduce the innocent: "Published with a title savoring of religion and written by a clergyman, it had an innocent look which admitted it to society where the ordinary licentious novel could not circulate." A magistrate, declining the request to issue an arrest warrant against the publisher, nonetheless agreed that the book was "nasty" and "particularly objectionable because written by a clergyman."
Shortly afterwards, a Boston judge deemed the book obscene, and fined a librarian (who protested that she had a long queue of patrons waiting to borrow the book) US$100 for circulating it. Keable himself professed surprise at the intensity of the reaction to the book, saying that his missionary and military experiences must have "blunted [his] perceptions as to what the general public felt." In response to the banning in Boston of another of his books,
Numerous Treasure, he wrote to his editor George Putnam that he had in the past month received fanmail from a bookseller, a request for his photograph from a girls' high school library, and "an intimation that I had been adopted as the literary patron of a class at an American university. I feel vaguely that Boston ought to be told."
The net effect of the
Simon Called Peter controversy was to make Keable a celebrity. The book became so well known that F. Scott Fitzgerald, who described the novel as "really immoral", gave it to protagonist Nick Carraway to read in his famous novel
The Great Gatsby, and had the character pronounce "Either it was terrible stuff or the whiskey distorted things, because it didn't make sense to me." The book's sequel,
Recompense, was optioned as a film by Warner Brothers, starring Marie Prevost and Monte Blue. Keable himself found the screenplay so altered from the original text, he wryly proposed that he write another novel based on it. His first visit to the United States, in autumn 1924, was announced in the
New York Times; he took in a production of the
Simon Called Peter stage play in New York before returning to Polynesia via New Orleans, Los Angeles, and San Francisco. On his return, the
Times printed a very lengthy letter from Keable on the subject of the origins of the cocktail, headlining it "Robert Keable, in His Tahiti Retreat, Makes a Case for Englishmen, or Their "Greek and Roman Ancestors," as the Inventors."
The same paper had received Keable's second novel, 1922's
The Mother of All Living, favourably; reviewer Louise Maundell Fields called it "Not only...better from an artistic point of view [than
Simon Called Peter]... its general outlook is both steadier and more mature. [...] the book has in it so much that is well done and worth while that one does not feel inclined to carp at its comparatively few weaknesses." On the whole, other reviews were less favourable. The characters in both
Peradventure and
Recompense were criticized for lacking depth: reviewers said they served only as vehicles for conveying different theoretical points of view. A later book, 1927's
Ann Decides, was dismissed succinctly by the
Chicago Daily Tribune as "tosh".
P.W. Wilson, in a
New York Times piece on contemporary religious literature two years after Keable had died, called Keable's life "a spiritual tragedy", and described his thinking as fundamentally contradictory:
"His mind, like rock, reveals by strata the volcanic and other experiences to which it has been subjected."
Keable's distinction between the historical and the traditional Jesus, Wilson argued, was ultimately muddled and internally inconsistent, his verdicts on the illiberality of the contemporary church at odds with his own abiding conviction.
Late in the 20th century Keable received some revisionist attention.
Simon Called Peter came back into print, with a recent edition published in 2008. Biographer Hugh Cecil, including Keable in his 1995 anthology of neglected Great War writers, concluded:
From early in his career he had used his talents to the full and seized life with both hands. His works, though seldom read now, were no mean achievement, intellectually or artistically, even if their high quality was rarely sustained throughout a whole book... Robert Keable was quintessentially the divided twentieth century man, yearning for self-realization and for a faith, and full of guilt and self-hatred. Yet as we have seen, Simon Called Peter is not an unhappy book... Robert's experience of war... seemed to reveal the nature of real goodness, loyalty, and love.—Cecil (1995) p.184.