A reader searching through the catalogs of manuscript libraries (punthi) in West Bengal, India, or Bangladesh, will easily come across a number of titles, sometimes of unknown authorship, marked with the note "sahajiya" (sahajiyā). Sometimes it is a librarian's postscript, in other cases the word sahajiya ("Sahajiyā") appears in the title, but this is rare. More often, the titles of these texts contain terms suggesting the esoteric nature of the work or suggest Vaishnava affiliation. Among the many Middle Bengali texts signed with the note "sahajiyā", the manuscript entitled Nigūḍhārthaprakāśāvalī or "Collection of Explanations of the Secret Meanings" or "Array on the Secret Meanings" stands out. Undoubtedly, it is an extensive text, considering that the vast majority of the so-called Sahajiya literature are short works – often fitting only on a few folios. Its uniqueness, however, lies in the commentary, explanatory nature of the text, the literalness of its descriptions of tantric methods (also erotic) and reflection on them. The hermeneutic effort of the NPV authors is unique from the background of Sahajiya literature, esoteric, obscure and devoid of commentary, which was most often transmitted orally.
The following monograph, containing translations of extensive fragments of NPV, together with an introduction and commentary, is the first attempt to present to the Polish reader fragments of Sahajiya literature, in the form of a Collection of Explanations of the Secret Meanings, a hitherto unpublished Middle Bengali work, based on a direct reading of the source text from the few surviving manuscripts. The choice of the work for translation was not accidental and resulted from the intention to present a rare, esoteric, and at the same time important text, addressed to the community of initiated adepts. On the other hand, a text that in many respects is typical of the literature Sahajiya, and because of its commentary character, more accessible than other contemporary texts. Despite this, NPV is still a difficult, esoteric text, requiring knowledge of other texts of the tradition, the specific, coded language of Sahajiya tantric literature (and the phenomenon of tantra in general) and Bengali culture in general. At the same time, it is the only direct translation of a premodern Hindu tantric text from a language other than Sanskrit, based on the original manuscripts rather than printed editions, or on the basis of an English translation. The translation of extensive excerpts from an eighteenth-century Bengali manuscript takes the reader into the extraordinary and mysterious world of medieval Bengali tantrics, famous for their esoteric literature and erotic rituals. Of the collection of Hindu tantric texts, the Sahajya corpus is one of the least known and understood. The work is thus unique not only in Poland, but also in the field of scientific world literature.