The Lettres persanes was an immediate success and often imitated, but it has been diversely interpreted over time. Until the middle of the twentieth century, it was its "spirit" of the Regency which was largely admired, as well as the caricature in the classical tradition of La Bruyère, Pascal and Fontenelle. No one had the notion of attaching it to the novelistic genre. The Persian side of the novel tended to be considered as a fanciful decor, the true interest of the work lying in its factitious "oriental" impressions of French society, along with political and religious satire and critique.
In the 1950s began a new era of studies based on better texts and renewed perspectives. Particularly important were the extensively annotated edition by Paul Vernière and the research of Robert Shackleton on Muslim chronology; also studies by Roger Laufer, Pauline Kra and Roger Mercier, which put new focus on the work’s unity and integrated the seraglio into its overall meaning. Others who have followed have looked into the ramifications of epistolary form, the structure and meaning of the seraglio, Usbek’s contradictions. Beginning about 1970 it is religion (Kra) and especially politics (Ehrard, Goulemot, Benrekassa) which predominate in studies on Letters persanes, with a progressive return to the role of the seraglio with all its women and eunuchs (Delon, Grosrichard, Singerman, Spector) or the cultural cleavage of Orient and Occident.
The American philosopher Marshall Berman devotes several chapters in his book The Politics of Authenticity (1970) to the radical humanism of the Persian Letters.