It is now widely accepted that there were many points of contact between manuscript and early print cultures; early printers, seeking to imbue their products with the authenticity of the previously dominant textual culture, attempted to make the products of the new technology appear as similar as possible to manuscripts in a number of respects. In studies of the history of the book in England, this continuity between manuscripts and prints has been recognised as an important issue. Nevertheless, some aspects still require detailed and extensive scrutiny, one of which is the rubrication of English fifteenth-century printed books. It was not until early 1484 that William Caxton, England’s first printer, acquired types for printing initials. Without such apparatus, Caxton and his contemporary printers provided spaces with guide letters for initials, so that the rubricator could insert letters after printing; underlines, paragraph marks and initial strokes were also often added after printing, as in medieval manuscripts. Previous scholarship has touched on the possibility of research in this area, but there has not been any systematic research to examine rubrications of English fifteenth-century books, considering to what extent these manuscript additions were systematized (or unsystematized) in the transitional phase between handwriting and the mechanical production of texts. This paper has examined nine extant copies of the Myrrour of the Worlde, as a case study. It has argued that it is possible to discern distinctive patterns of rubrication among them, presenting possibilities and challenges of studying patterns or house styles of rubrications in Caxton's early books.