Turkish-Islamic literature encompasses a rich textual tradition extending from the Ottoman period to the present, formed over different historical stages. A significant portion of this literary heritage has survived in the form of manuscripts, which have become multi-layered and multifaceted sources for researchers, both in terms of their textual content and their physical characteristics. Containing information related to various scientific disciplines, literary genres, and cultural heritage, these works draw attention not only for their textual value but also for their material aspects such as transcription techniques, bookbinding arts, and paper production methods. This study examines Turkish-Islamic manuscripts written in Ottoman Turkish and preserved in Europe, particularly in the Library of Leiden University. The research addresses the historical context of these manuscripts, the process of the collection’s formation, their physical structures, preservation conditions, and current accessibility. The foundation of the Leiden collection is the Legatum Warnerianum manuscript archive, created in the 17th century primarily through the efforts of Levinus Warner and many other Orientalists. This archive was compiled from works obtained in different regions of the Ottoman Empire and transferred to Europe through the networks of the period’s intellectual circles. The collection contains numerous works in the fields of tafsir, fiqh, kalam, Sufism, and literature, which have been evaluated in detail in terms of both content and form. Codicological analyses include bookbinding structures, paper types, watermarks, and transcription records; paleographic analyses focus on script types, line arrangements, and writing styles. Methodologically, the study employs both the digital collection system of Leiden University and its physical archive documents. Furthermore, a comparative analysis was carried out with the cataloging, preservation, and digitization practices applied in manuscript libraries in Türkiye. In this way, the processes of preservation and access to manuscripts have been evaluated within both European and Turkish contexts. The research also investigates, in light of historical documents, the routes by which the manuscripts reached Europe, how they were classified and cataloged there, and the ways in which they have served as sources for scholarly studies. The study concludes that the Leiden University collection possesses an advanced structure in terms of content richness, physical preservation, and digital accessibility. With these features, the collection provides methodological examples for manuscript institutions in Türkiye and serves as a valuable reference for textual editing, comparative literature, cultural history, and philological research.