In 1350, the Italian humanist and poet Francesco Petrarca (Petrarch) decided to form a collection of all his correspondence. The letters deal with multifarious topics, switch between narration and instruction, and the personal and the general, and are addressed to various of his learned friends and contemporaries. They are a treasure trove for the history of ideas. This is the first complete German-language edition of the famous 24 books of the Epistolae familiares; they have been translated from the Latin by Prof. Berthe Widmer, an acknowledged authority on Petrarch. The translation is accompanied by a detailed commentary on the texts, giving factual information on aspects which are largely unknown today, for example on persons, authors and places mentioned. Access to the letters is further facilitated by an annotated index of the addressees and an overview of the contents of the letters. A detailed introduction locates the letters in the context of Petrarch's complete works and his age. The letters represent a most important document in the history of literature and are of inestimable value for all literary scholars and for historians and historians of philosophy.