Whereas during the first half of the eighteenth century the expression ‘oświecony’ in Polish was nearly always a religious metaphor, between the 1760s and the early nineteenth century the noun ‘oświeconie’ became secularized, broadened and given a quite revolutionary new meaning, denoting an intellectually grounded, rational and true understanding of things in contrast to how traditional religious authority understood things. This is well known to scholars and students alike. But the question now arises, with the rise over the last 20 to 30 years of ‘Radical Enlightenment’ as a fundamental new category in the humanities, how much has this category applicability in the Central European context? Studying book history and print culture, I shall argue, helps us to determine that in fact it does.