application/pdf 論文(Article) The object of the following paper is to review the present status of the experimental and theoretical studies on the pion-pion strong interaction. The historical development of the pion-pion resonance is considered in Sec.1. In Sec.2, the pion-pion interaction is treated with respect to the pion-nucleon scattering reaction. The pion production by pion and pion photoproduction are considered in Sec. 3 and Sec. 4, respectively. Sec. 5 is devoted to the nucleon electromagnetic form factors.