This volume contains the proceedings of the 19th International Symposium on Algorithmsand Computation (ISAAC 2008), held on the Gold Coast, Australia, December 15 17, 2008. In the past, it was held in Tokyo (1990), Taipei (1991), Nagoya (1992), Hong Kong (1993), Beijing (1994), Cairns (1995), Osaka (1996), Singapore (1997), Daejeon (1998), Chennai (1999), Taipei (2000), Christchurch (2001), Vancouver (2002), Kyoto (2003), Hong Kong (2004), Hainan (2005), Kolkata (2006), and Sendai (2007). ISAACis anannualinternationalsymposiumthatcoversthe verywide range of topics in the ?eld of algorithms...