They support the German Humanist scholar Johann Reuchlin and mock the doctrines and modes of living of the scholastics and monks, mainly by pretending to be letters from fanatic Christian theologians discussing various topics.
The title is a reference to Reuchlin's 1514 book Epistolae clarorum virorum (English: Letters of famous/bright men) which provided a collection of letters to Reuchlin on scholarly and intellectual matters from eminent German humanists such as Ulrich von Hutten, Johann Crotus, Konrad Mutian, Helius Eobanus Hessus, and others, to show that his position in the controversy with the monks was approved by the learned.
The Latin adjective obscurus ("dark, hidden, obscure") is the opposite of clarus ("bright, famous, obvious") used in the title of Reuchlin's book.
Grätz had made himself odious to the liberal minds of the time by what they saw as his arrogant pretension, his determined hostility to the spirit of the age, and his lax morality.
The collection was published anonymously, and the authorship has been a fertile subject of controversy, but the main portion of the letters are attributed to the humanists Crotus Rubeanus a.k.a.