The letter was written as an introduction to an edition of Dante's Divine Comedy that Foscolo intended to prepare in 1824 for the publisher Pickering but which was never completed; the dedication “To the Padua publishers of the Divine Comedy” was meant to justify the arbitrary placing here of a work that had political and autobiographical content that was not very coherent with an edition of Dante. A incomplete draft of Lettera Apologetica was found by Giuseppe Mazzini in 1840 when, exiled in London, he went to Pickering to complete his research into Foscolo's unpublished works; the text was printed in the Foscolo edition of Scritti politici inediti raccolti a documentarne la vita e i tempi (Unpublished political writings collected to document the life and times), edited by Mazzini and published in Lugano in 1844.

Composed less than two years before the author's death, it is a political and intellectual testament with which Foscolo intended to defend himself from the accusations made against him by the Milanese literary figures, at the same time offering his interpretation of the political picture and of the profound changes of the previous years. With emphatic prose broken by continual alternation between narrative, reflective and polemic modalities, Foscolo recalled the last part of his stay in Italy and, above all, the controversial events of the tragic 1814 and the time of his departure from Milan in 1815. In it he aims to construct an apologetic self-portrait, presenting himself as a Plutarchian hero moved by pure, absolute sentiments, unjustly persecuted by corrupt Italian literary figures who were slaves to power. Starting from a conception of politics in which the detachment of exile takes on connotations of strong individualism, Foscolo reiterated his intellectual freedom and his faithfulness to patriotic ideals, and he contested all commercialization of literature and the enslavement of the literary figure to power, as he had done previously in the Pavia Oration.