Arcana, meaning specialised knowledge that is mysterious to the average person, is a tough barred crossword with cryptic clues. This puzzle has been compiled for many years by Roger Prebble. Due to the highly-intersecting nature of the grid, some of the answers might be relatively obscure, so access to dictionaries, in particular Chambers English Dictionary, 1988 Edition, would be helpful to the solver.
The puzzle was inspired by The Observer's barred crossword, compiled by Jonathan Crowther, whose pseudonym is Azed.
Incidentally, the pseudonyms of the first two Observer compilers were respectively Torquemada and Ximenes, the names of Grand Inquisitors (Tomás de Torquemada, 1420-1498, Ximenes de Cisneros, 1436-1517) during the Spanish Inquisition. With the advent of Azed, it seemed this tradition had been lost, but in fact another of the Grand Inquisitors, successor to Torquemada, was Deza (Diego Deza, 1444-1523); so the name Azed seems beautifully apt for a compiler of such a fiendishly difficult crossword.