PageHeader : Funkcialaj Ekvacioj, 41 (1998) 167-188 Title : The Lifespan of Solutions to Quasilinear Hyperbolic Systems Title : in the Critical Case AuthorInfo : By AuthorInfo : Akira HOSHIGA AuthorInfo : (Kitami Institute of Technology, Japan) AuthorInfo : Dedicated to Professor Rentaro Agemi on his 60th birthday section : 1. Introduction section : 2. Preh.minaries section : 3. The proof of Theorem section : Appendix section : References