Daisaku Ikeda's lecture on Nichiren Daishonin's writing. In this lecture, Daisaku Ikeda examines the central theme of Buddhist philosophy, namely the meaning of life and death and the overcoming and transformation of suffering. This, according to the author's commentary, is the essential reason that animates the Buddha's compassion and drives him to face every kind of difficulty in order to lead living beings to supreme enlightenment. In the Lotus Sutra, this desire of the Buddha is referred to as the "one great reason" (ichidaiji). Through an in-depth examination of the writing, the author expounds the philosophical principles that Nichiren considered essential for his disciples to achieve Buddhahood.