Brooke began her literary career with The Old Maid (1755-6), a witty essay periodical that she operated under the pseudonym "Mary Singleton, Spinster," and that was reprinted as a single volume in 1764. This periodical staging interactions between a vivid central voice, the perspectives of other contributors (probably fictional), and reader correspondence (much of which may also have been fictional), it is no surprise that her first full-length literary effort was a drama, Virginia: A Tragedy (1756), which she was unable to get staged. Her first two novels similarly capitalized on dramatic dialog skills in their epistolary form. The first, The History of Lady Julia Mandeville (1763), was issued anonymously. It was quite successful, going through multiple editions in its first year. Around the time of its publication, Brooke left England, the country where she was born and lived her early life, to join her husband, who was serving in Canada as part of the British army. The History of Emily Montague by "the Author of Lady Julia Mandeville" (1769) capitalizes on her Canadian experiences. Though not as successful as her previous novel, this one was also well received and is lauded by some as the first Canadian novel. A second anonymous Canadian novel, All's Right at Last (1774), has tentatively been attributed to Brooke largely on the basis of its subject matter. The Excursion (1777), with its lampoon of actor and stage manager David Garrick, followed next. At this point Brooke began to achieve some dramatic success with stagings of her tragedy Siege of Sinope in 1781, and two comic operas, Rosina in 1782 and Marian in 1788. Her final novel, The History of Charles Mandeville, was posthumously published in 1790. In addition to her own creative works, Brooke translated several from the French, including Letters from Juliet Lady Catesby (1760), an epistolary novel by Marie Riccoboni.