This volume constitutes the twenty-first IJCAI conference. The locations and times of all twenty-one IJCAI conferences are as follows: 21 IJCAI-09: Pasadena, California, USA (July 11–17) 20 IJCAI-07: Hyderabad, India (January 6–12) 19 IJCAI-05: Edinburgh, Scotland (July 30–August 5) 18 IJCAI-03: Acapulco, Mexico (August 9–15) 17 IJCAI-01: Seattle, Washington, USA (August 4–10) 16 IJCAI-99: Stoc...

The latest in a series of natural language processing system evaluations was concluded in October 1995 and was the topic of the Sixth Message Understanding Conference (MUC-6) in November, co-chaired by Ralph Grishman (NYU) and Beth Sundheim (NRaD). Participants were invited to enter their systems in as many as four different task-oriented evaluations. The Named Entity and Coreference tasks enta...