Stoppard's one of the great modern playwrights, of course, and he certainly loves radio. The format complements his wit and humor and playful, detailed allegories. The prize of this collection is his radio masterpiece "Artist Descending a Staircase," which tackles the artifice of perception and the "blindness" of radio in a way that is both moving and intellectually exciting. The other plays are of less consequence, though entertaining. It is "Artist," with all its clever secrets and sad reflections on art and life, that rises above the rest. Aided in no small part by the hidden presence of the sly ghost of Marcel Duchamp.