The practice of writing for third parties, often done on commission and/or for profit (pro pretio ), remains a largely neglected aspect of late medieval manuscript culture. Although professional scribes and book artisans played a central role in the production and circulation of manuscripts, evidence of their economic activities is sparse and fragmented, leaving our understanding of the financial aspects of manuscript production, whether in secular or religious settings, still limited. As a result, it is challenging to assess the value of handwritten books, estimate the costs of their creation, or trace the financial exchanges they entailed. Likewise, knowledge about the individuals — both men and women — or workshops engaged in the professional manuscript production and trade during the late Middle Ages remains elusive. To advance current debates on manuscript production and introduce new perspectives to the field Writing for Third Parties: Commercial Manuscript Production in the Late Middle Ages brings together eight articles that delve into the material, financial, and social dimensions of manuscript production in the late medieval Low Countries and the neighbouring regions of Hainaut and Alsace. The contributors illuminate the commercial viability of manuscript-making, the individuals and workshops involved, and the complex networks of labour, trade, and patronage that shaped medieval text culture. Emphasising the importance of interdisciplinary research and archival inquiry, this collection repositions manuscript production as both a professional craft and an economic enterprise, thereby reinvigorating scholarly interest in the commercial facets of medieval literary culture.