The manuscripts of the University Library in Poznań are very diverse in terms of chronology (10th–21st centuries), subject matter and provenance. The collection contains many valuable artifacts and source materials, particularly from the Wielkopolska region. The diversity of its holdings reflects the Library's history, from its founding in 1901 as the Kaiser-Wilhelm-Bibliothek, its renaming in 1919 as the Poznań University Library, and the Polonization of the collection in the interwar period, to the period of the Staats- und Universitätsbibliothek (1939-1945) and the campaign to secure book collections that survived World War II (1945-1950). The collection includes 45 codices – medieval manuscripts (13th century - first half of the 16th century), mostly from church collections in Greater Poland, primarily monasteries (as of 2016 included in the National Library Resources). In addition to the codices, the medieval manuscripts also include two documents (legal acts) from the 15th century and nearly 30 fragments, mainly parchment, of manuscripts from the 10th-15th centuries, which include many valuable relics of medieval European writing.
As part of the post-war campaign to secure surviving book collections, the Library received manuscripts from Greater Poland manor libraries and landowner archives, both Polish (the Skórzewskis from Czerniejewo-Radomice and Lubostroń, the Mielżyńskis from Pawłowice and Chobienice, the Mycielskis from Kobylepole, the Kościelskis from Miłosław and the Żółtowskis from Niechanów, the Pawłowskis from Grudzielec, the Radolińskis from Jarocin and the Trąmpczyńskis from Dębłów near Gniezno) and formerly German (among others. the von Massenbach family from Białokosze, the Stolberg-Wernigerode family from Borzęciczki near Krotoszyn, the Maltzan family from Milicz, Baron Joachim von Loesch from Jabłonna near Rydzyna, as well as part of the archives and book collections of the Baltendeutsch (Baltic Germans) and the archives and collections of Masonic lodges from all over Europe collected by Himmler).
Another group of manuscripts consists of the archives of Polish and German institutions and associations, primarily those in Greater Poland, including the Historische Gesellschaft für die Provinz Posen (1885-1945) and the Historische Gesellschaft in Polen (1919-1939), the records of the Trade Union of Polish Writers in Poznań (from 1921-1933), the Polish-Italian Society in Poznań (1932-1934), and the archives of the Polish School Museum in Lviv. A separate manuscript category comprises the legacies (or fragments thereof) of famous social activists, writers, composers, musicians, musicologists, and professors of Poznań universities. A significant portion of the manuscript collection consists of memoirs, primarily wartime ones – written by participants and witnesses of the events: the Greater Poland Uprising (over 200 works from 1968), as well as occupation-era memoirs by students
of the Faculty of Law and Economics at the University of Poznań, the Poznań Academy of Economics, and the Szczecin Academy of Economics (nearly 1,800). A significant part of the manuscript collection is the Stammbuch collection comprising books of friendship (Latin: alba amicorum, also known as memory books) from the 17th to the 20th centuries.