Liber sine nomine

The Liber sine nomine (The Book without a Name) is a collection of nineteen personal letters written in Latin by Petrarch, the fourteenth-century Italian poet and Renaissance humanist. Because of their harsh criticism of the papacy at Avignon, he withheld them from his larger collection, the Epistolae familiares (Letters to Friends), and gathered them in a separate book. In this way, Petrarch reasoned, a reader could discard this collection without losing the other letters, which could thus be preserved for posterity.

The letters were sent to his closest friends, many of whom were well-known public figures. To avoid revealing their identities, Petrarch left out the names and published the book without a name on any of the letters. Among the recipients were Philippe de Cabassoles, bishop of Cavaillon; Cola di Rienzo, a political leader; Francesco Nelli, secretary to the bishop Angelo Acciaioli I; and Niccola di Capoccia, a cardinal. The final letter includes an appendix addressed to Charles IV, Holy Roman Emperor.

The title has been reused by other works, including those by Lady Morgan and Thomas Charles Morgan (1841), Theodore Annemann (1931) and Kit Williams (1984).