1909 to 1930

Wilson's literary career had begun before she became a civil servant. In 1909 under the pen name Monica Moore, she wrote a short story, "The Ordeal", printed in The Nation; it featured the miseries of mill workers.^[7] The following year she published a novel, The Story of Rosalind Retold from her Diary, a tale about of a talented woman writer and artist whose short life was divided between the arts and social work. In the Dictionary of Literary Biography, Margaret Carter describes the heroine as "a restless and haunted woman, whose fall from her galloping horse may have been her means of joining her recently deceased young son".^[8]

In 1924 Wilson made her first sortie into literary biography, with These Were Muses, a brief introduction to the works of nine 18th- and 19th-century women writers whose renown, according to Wilson's preface, "has faded or … remained unfulfilled." Wilson observes that her book is "not intended for the student, but for the curious general reader who will have come across the names of the subjects of these papers in histories or literature."^[9] She gives brief biographies of, and quotes extensively from, the playwrights Susannah Centlivre and Frances Sheridan; the novelists Charlotte Lennox, Sydney Morgan and Jane Porter; Sara Coleridge, author of children's verse; Hester Chapone, writer of conduct books; Mary Ann Kelty, religious writer; and Fanny Trollope, novelist and travel writer.^[8]

Wilson's first full-length biography, The Life of William Blake, was published in 1927, the centenary of the subject's death. Wilson concentrated on Blake's life-story and his writings, although she did not neglect his paintings.^[10] The New York Times thought her prose "rather uninspired", but found the book "careful and impartial … certainly the best and most authoritative life of Blake yet written".^[11] When a revised edition was published in 1949, The Manchester Guardian commented, "Miss Wilson may have assumed rather too easily the unity of mystic, poet, and artist in Blake, but she has told his story more fully and sensibly than anyone else."^[12]

In the late 1920s Wilson corresponded on a literary topic with the writer G. M. Young, who before their retirements from the public service had been a colleague at the Ministry of Reconstruction. She asked him down for the weekend to her house at Oare, near Marlborough, Wiltshire. As their publisher, Rupert Hart-Davis, put it in 1956: "To cut a long story short, he stayed there for twenty-five years, until M.W. died a year or two ago. There was, so far as I know, no just cause or impediment why they shouldn't have married, but they just didn't. I'm sure their relationship was entirely intellectual and companionable."^[13]

1930s

After a four-year gap Wilson's next book was a study of Sir Philip Sidney (1931), which combined a biography with literary criticism of his writings, contrasting his disciplined poetry with his elaborate and ornamented prose style.^[14] The book was praised by reviewers, although her own prose style was thought "here and there rather dryly matter-of-fact".^[15] The Times concluded its review:

In 1932 Wilson was made an Associate of Newnham College.^[1] In the same year she produced the first of two books for the "Short Biographies" series of her publisher, Peter Davies. Her Queen Elizabeth, a 180-page study of Elizabeth I, was moderately well reviewed. The New York Times thought Wilson's attempt to disentangle Elizabeth's personality from her actions led to "an outline portrait made of broken lines that do not quite sufficiently explain themselves".^[16] The Spectator commented, "No one, after reading Miss Wilson's book, will fail to understand how it was that Elizabeth's reign is one of the most famous in English History, and still the most glamorous of all."^[17] Wilson's Queen Victoria the following year was politely received, with reservations as to whether the author gave her subject enough credit for "native intelligence and political common sense".^[18]

Wilson contributed a chapter on holidays and travel to the two-volume Early Victorian England edited by Young and published in 1934.^[19] In 1935 she wrote the opening and closing chapters of R. B. Lambert's Grand Tour: A Journey in the Tracks of the Age of Aristocracy (1935).^[20] Reviewing the book, James Laver remarked that it took the reader from the days of the Wife of Bath to those of John Ruskin.^[21] In 1937 Wilson contributed a chapter on Mary Wollstonecraft to Bonamy Dobrée's collection of essays From Anne to Victoria.^{[22][n 3]}

Jane Austen and Some Contemporaries (1938) comprises biographies of Jane Austen and seven other female writers of the period.^{[24][n 4]} The book was described by The Manchester Guardian as very thorough in its understanding of the people of Austen's time, though a little difficult to follow for a reader unfamiliar with the time period.^[26] In this book, Wilson ranks Austen as at least the equal, if not the superior of Mary Wollstonecraft in advocacy of equal rights for women.^[27] Wilson's biographer Elaine Harrison comments that this demonstrates Wilson's "preference for a more subtle advocacy of women's claims for equal consideration".^[3]

Last years

By the end of the Second World War most of Wilson's books were out of print. Hart-Davis, who already published Young's books, commissioned revised editions of The Life of William Blake (1948) and Sir Philip Sidney (1950), and Wilson's last book, an anthology, Johnson – Prose and Poetry (1950). This was a 900-page collection of Samuel Johnson's writings. The prose included excerpts from Rasselas, A Journey to the Western Isles, the Letter to Lord Chesterfield, the preface and plan of the Dictionary, Lives of the Poets and essays. Some of Johnson's poetry – both Latin and English – was also included. The Times Literary Supplement said it was "a book for which the lover of Johnson may be grateful and one, moreover, likely to make more lovers of Johnson".^[1]

Wilson died at a nursing home in Putney, London, on 26 October 1954 at the age of 82.^[3]