APLAS 2005 was the Asian Symposium on Programming Languages and S- tems, held in Tsukuba, Japan in November 2 5, 2005. It was the latest event in the series of annual meetings started in 2000 by Asian researchers in the ?eld of programming languages and systems. The ?rst three were organized as wo- shops, and were held in Singapore(2000), Daejeon (2001), and Shanghai (2002). Theenthusiasmthere, encouragedbytherichproductionoforiginalresearch- pers, and the support of the internationalresearchcommunities in programming languagesandsystems, ledtothe?rstAPLASasasymposiuminBeijing(2003), followed...