EPISTOLA DE LA LETTERE NUOVAMENTE Aggiunte ne la Lingua Italiana. [and] DUBBII GRAMMATICALI

Sm. folio. The bottom margin of two leaves are shaved, affecting the last line of text; the final leaf lightly spotted. An attractive copy of a TYPOGRAPHICALLY SIGNIFICANT book.
The second edition of Trissino's letter to the Pope offering suggestions for orthographic reform of the Italian language, along with the First Edition of his more important Dubbii Grammaticali in which these proposed changes are spelled out. With Janicolo's Golden Fleece device on the title-page with the initials PT and IA on either side of the tree [there are two states of the printer's device].
The works are printed in Lodovico degli Arrighi's first italic type, the (truncated) font used for the first edition printed by Arrighi in Rome in 1524. According to Mortimer, "For the purpose of printing Trissino's text, Arrighi added to his italic the new characters proposed by Trissino for the Italian alphabet."[i.e. differentiating between the open and closed "o" and "e" and by using Greek omega and epsilon; the replacement of consonantal "i" and "u" by "j" and "v," and a distinction between hard and soft."] Nothing is known of Arrighi after the sack of Rome. Subsequently, Trissino presented the font matrices to Janicolo in Vicenza, to be used in the printing of this edition, which was written in response to attacks on his proposed reforms. A handsome book!
See: Mortimer/Italian 507 [with two illustrations]. Adams T-951. Johnson. Type Designs. 103. (Inventory #: 4500.1529)