Judah the Pious (1972), a medieval quest tale drew the reader to ultimate cosmic riddles; here Miss Prose uses the vehicles of Italy's 16th century commedia dell' arte to point up similar metaphysical ironies. In this popular, usually outdoor theater form, roles were as fixed as the galaxies: Arlequin, Pantalone, Columbina, the Doctor, etc. Flaminio Scala (the Captain), Francesco Andreini (Arlequin) and his wife Isabella were historical personages, but under Miss Prose's fanciful attention, they become like the other members of ""The Glorious Ones"" -- human beings both formed by and shrinking within the roles which gave them their essential existence. Flaminio withers from near-hero to comic, impotent pursuer of a slut; Francesco, once the acrobatic trickster becomes alternately a creature of poignant love and aggressive ambition; and Isabella is the sad/mad acolyte of the moon -- beautiful and virginal -- until the shadow of human love brings her back to earth and ""pretty tricks."" The scenario flows on and off stage -- it's all the same comedy -- until Flaminio kills himself in the ultimate improvisation before the audience and Isabella, forced to die rather than have a baby (that's not the stuff of a good show) speculates from heaven. The angels are happily certain that all human dramas are the same and interchangeable, but then -- why would a beggar want all the gold in the world? Why would an actor yearn for immortality? Why would a young girl dream of the moon? Do men create their roles, or are they manipulated by them -- and is outsized human passion which won't be confined to the script the' greatest joke of all? Again Miss Prose finds infinite space in her very special genre and writes with force, color and remarkable efficiency.