On behalf of the organizing committee I would like to welcome you all to the second Asian Symposium on Programming Languages and Systems (APLAS 2004) held in Taipei on November 4 6, 2004. Since the year 2000, researchers in the area of programming languages and systems have been meeting annually in Asia to present their most recent research results, thus contributing to the advancementofthisresearcharea.ThelastfourmeetingswereheldinSingapore (2000), Daejeon (2001), Shanghai (2002), and Beijing (2003). These meetings were very fruitful and provided an excellent venue for the exchange of...