Identity, history and the status of others loom large in a knot of plays at the Edinburgh International Festival and Fringe.

The theatrical side of the International Festival - this year themed "Artists Without Borders" - began last weekend with TR Warszawa's Dybbuk , a blend of two pieces about possession and obligation to the past. In Szymon Anski's 1920 play, young Lea is possessed on her wedding day by the spirit of the young man to whom she had previously been betrothed; in Hanna Krall's contemporary story, Polish-American Adam is sporadically inhabited by a half-brother who died in the Warsaw ghetto. In Krzysztof Warlikowski's adaptation, Anski's story simply segues into Krall's rather than being tricksily interwoven.