TEZUKA Osamu (1928-1989) was one of the most important manga writers in Japan; his contribution to the popularization of manga and anime cannot be overstated. Tezuka's handling of the confrontation and reconciliation between human and machine, and his vision of humanity with a global perspective, for example, have fascinated many readers both domestically and internationally. Following his creation of a human robot character, Astro Boy (1951), Tezuka frequently wrote about the various impacts of science and technology on humanity. As Tanaka explains, Tezuka witnessed the destructive consequences brought about by the particular use of science and technology during the U.S. bombings of Japan during WWII, which in turn motivated him to explore themes such as war, peace, and humanity in his works. This essay introduces Tezuka's family background and his upbringing, and discusses how his history and personal experience of the war influenced him in the creation of manga heroes and narratives that are closely connected to real-world problems, such as the Vietnam War and nuclear issues. Focusing on Tezuka's early works, the author analyzes some of the most representative manga expressing the artist's observations and ideas about war and peace, as well as his imagination of the future.