For its forthcoming trip to the Edinburgh Festival, the Abbey Theatre has chosen one of its best offerings of recent years. Tom Murphy's place in the pantheon of Irish theatrical genius is unassailable. His cutting-edge themes, and the passions with which he infuses them, have made even his failures - the price of his pioneering - worth the debates they invariably animate. The Wake, based on his novel The Seduction of Morality, is his 24th play. It is set in the small- town territory he has uniquely explored, and his characters and their all-too- human predicaments touch a universal nerve. Before it travels, it is revived for a short run, with only one change to the cast of its premiere in January 1998.