Carolyn Keene is not an individual author but a collective pseudonym used for several mystery series, most notably the Nancy Drew books, produced by the Stratemeyer Syndicate. The syndicate's founder, Edward Stratemeyer, initiated the practice of hiring writers to produce manuscripts for these popular series. Mildred Wirt Benson was the primary writer for the early Nancy Drew novels, receiving a flat fee and relinquishing all rights to her work. After Benson's involvement lessened, Harriet Adams, Stratemeyer's daughter, took over, revising existing stories and commissioning new ones. Numerous other writers, including Leslie McFarlane and James Duncan Lawrence, also contributed under the Keene name. The syndicate later changed publishers, a move that led to legal disputes, and eventually, the ownership of the Stratemeyer Syndicate and its associated series transferred to Simon & Schuster.

The name Carolyn Keene was established by the Stratemeyer Syndicate, a content creation company founded by Edward Stratemeyer. The syndicate's business model involved conceiving popular series and then hiring ghostwriters to produce the books under a consistent, fictional authorial identity. This practice allowed for the rapid output of numerous titles and maintained a unified brand for series like the Nancy Drew Mystery Stories and the Dana Girls mysteries. The writers were contracted to forfeit all rights to their creations and maintain strict confidentiality, ensuring the illusion of a single author persisted for decades. This approach was foundational to the syndicate's success in mass-producing juvenile fiction.

While Carolyn Keene is the credited author, the actual writing was performed by a succession of authors. Mildred Wirt Benson is recognized as the most significant early contributor, penning a substantial number of the initial Nancy Drew novels. Following her, Harriet Adams, daughter of Edward Stratemeyer, played a crucial role in revising earlier works and developing new storylines, effectively guiding the series' evolution. Beyond these primary figures, a diverse group of writers, including Leslie McFarlane, James Duncan Lawrence, and many others, contributed to the vast body of work attributed to Carolyn Keene. Even individuals outside the direct writing staff, such as Harriet Otis Smith, who conceived Nancy's friends Bess and George, and editors at Grosset & Dunlap, influenced the final output.

The Nancy Drew series, published under the Carolyn Keene pseudonym, experienced significant shifts in its publishing arrangements. Initially, the books were released by Grosset & Dunlap. However, in 1979, the Stratemeyer Syndicate made the decision to move to Simon & Schuster as their publisher. This change prompted a legal challenge from Grosset & Dunlap, who argued it constituted a breach of contract. The courts ultimately ruled in favor of the Stratemeyer Syndicate, affirming their right to select their publisher. Later, in 1985, Simon & Schuster acquired the Stratemeyer Syndicate, and the ongoing management of the Nancy Drew books transitioned to Mega-Books, a book packager.