Frank McGuinness now enjoys a high international profile. His plays - originals and adaptations, as of Chekhov, Brecht and Ibsen - have conquered London and Broadway. Dolly West's Kitchen has just concluded a successful run in the Old Vic, and his version of Peer Gynt will soon be revived at London's Royal National Theatre, directed by Conall Morrison. His opening nights are as apt to be in London as in Dublin, which has to wait its turn. Mutabilitie, which had its first run at the RNT in 1997, arrives here at last, opening in the Samuel Beckett Theatre next Wednesday. It is set in 16th-century Munster, where Celtic myth collides with Spenser and Shakespeare; an intriguing McGuinness mix, here produced by the award-winning Theatreworks company, directed by Michael Caven.