So, appropriately, I'm listening to The Professor and the Madman on audible. It is the story of the creation of the Oxford English Dictionary.... which is much more fascinating than you might think....and just a wee bit mysterious...
Mysterious (mistîe · ries), a. [f. L. mystérium Mysteryi + ous. Cf. F. mystérieux.]
1. Full of or fraught with mystery; wrapt in mystery; hidden from human knowledge or understanding; impossible or difficult to explain, solve, or discover; of obscure origin, nature, or purpose.