He is a leading scholar of late eighteenth- to early nineteenth-century drama and theater; of the Cockney School of poets, which included, among others, John Keats, Percy Shelley, and Leigh Hunt; and of the poetry of William Wordsworth.
Cox's early work helped spark a revival of interest in the drama of the romantic period.
He most recently published a book on the late poetry of Wordsworth, showing how the poet responds to his younger contemporaries.
In 2008, Cox was selected to give a plenary address at the annual meeting of the North American Society for the Study of Romanticism (NASSR) at the University of Toronto.
Cox received the Keats-Shelley Association Distinguished Scholar Award in 2009 for his work on the Keats-Shelley circle, and the 2011 meeting of NASSR at Brigham Young University acknowledged his book In the Shadows of Romance: Romantic Tragic Drama in Germany, England, and France for its "significant impact on the field"[1] of Romanticism.