La Soeur (1645) is one of the liveliest and most successful comedies by Jean Rotrou. It is an ingenious adaptation, long unidentified, of an Italian comedy, La Sorella (c.1584), by the polygraph Giambattista Della Porta. Sometimes it remains close to the original text, while at other times it is bold in eliminating superfluous material and in imparting a convincingly French flavour to the dialogue. The introduction to this new edition...