This bewitching tale of a very, very old woman, shuttered in a Roscommon asylum which is about to be closed -- and alternating between entries in her secret diary (kept beneath the floorboard) and that of her psychiatrist -- is, in addition, a marvelously rich potrait of the events of 20th century Ireland: the two world wars, civil war, formation of the Irish Republic and the influence of the Catholic church.  (IRE246, $15.00)