The main objective of Panzera's very substantial book is to reconstruct a long and complex tradition that transformed letter writing into a new genre, manifested by the publication of a large number of treatises on epistolography and letter collections (both in Latin and vernacular) in the fifteenth and sixteenth centuries, in Italy particularly. As its subtitle indicates, this book aims to explain the evolution from the model of the orator, taken from antiquity, to the new figure of the secretary. To this figure Francesco Sansovino dedicated the celebrated Del Secretario (1564), meant to teach how to properly write letters of any kind and to provide models and illustrious examples, such as copies of letters by princes, and the titles that had to be used in addressing all people, from noblemen to commoners.

Sansovino's work was addressed to the head of an office charged with the delicate duty of public communication. However, it was not just the secretary who needed instruction on how to properly write a letter: the abundance of letters still preserved in libraries and archives prove the importance of their exchange as a social and cultural practice in the early modern age, very well known by all historians. Sansovino's work had great success, but it was not entirely original. Not only did it belong to a long tradition rooted in classical epistolography and the teaching of rhetoric, but the groundwork was prepared by a large group of works, including Erasmus's De Conscribendis Epistolis (On letter writing). Along with Erasmus, and possibly others, the Italian humanist Francesco Negro (Franciscus Niger, 1452–1523) seems to have provided a direct model for Sansovino's work, with his Opusculum Scribendi Epistolas (Little work on letter writing), first published in 1488.

Seven chapters form the main section of Panzera's book, which opens with an introduction to the field of studies that prepared the context for a wide reconstruction such as the one under proposal. The first chapter provides an overview of the flourishing of letter writing in the sixteenth century, when publications appeared that served various purposes, including self-promotion and avoiding censorship. It was in this context that Sansovino published his work, which is analyzed in depth in the final chapters (187–268). In the central section of the book, important questions are addressed about classical and medieval sources; the evolution of the models; the role played by education and teaching practices; and the most influential authors. Much attention is given to Francesco Negro's treatise (99–164), in order to assess its actual influence and to ascertain whether there were elements of continuity (from late medieval teaching to early modern practices) that coexisted with new trends (represented by Erasmus). Negro wrote his book for students of law in Padua, who wished to learn how to master not only the Latin of oral communication (the high register of the speech) but also the more familiar register, as found in Cicero's Epistulae ad familiares (Letters to his family, 106).

Negro arranged the text in three sections: a treatise on letter writing, including models and formulas; a collection of grammar rules; and a list of titles for addressees. Many editions followed the first one in the fifteenth and sixteenth centuries: eighty-four are listed in the introduction of the final section, which offers a valuable comparison of the models taken from both Negro's and Sansovino's texts (279–376). There are some imprecisions in the list of editions: the identifier assigned to them in bibliographies is not given, which makes it troublesome to ascertain possible discrepancies (e.g., why some fifteenth-century editions are not in the ISTC); also, the editions printed in 1500 are listed under the sixteenth century. However, this does not affect in any way an overall appreciation of the work. The wide perspective and the amount and quality of information provided make Panzera's book a very profitable read for a broad audience of early modern historians, especially those interested in cultural and social history, including the history of education, of literature (both Italian and Neo-Latin), and of the book.