This is Yoshino Genzaburô's long story for children published in 1937 as volume No.5 of Nippon Shôkokumin Bunko [Series for Japanese Young Nationals] series edited by Yamamoto Yûzô. It deals with highly ethical minds based on liberalism and humanism, being a pioneer of the best moral stories in Japanese children's literature. It is still read as a conscientious piece of work.
 The story concerns a junior high school boy Honda Jun'ichi alias Koperu-kun, who grows up spiritually through association with his classmates and advised by his uncle. The problems of Japan's social system and the true nature of human beings are described from the boy's point of view.
 At first Yamamoto intended to write the story, but, due to his illness, Yoshino wrote it on his behalf. The first edition bears Yamamoto's name as well, as a co-author. When it was published as one of Kaitei Nippon Shôkokumin Bunko [Revised Series for Japanese Young Nationals] series in 1948, only Yoshino's name was adopted as the single author. In the same year, Oki Naotarô made a stage version of the story and published it as Kimitachi wa Dô Ikiruka: Koperu-Kun to Sono Nakama [How Should You Live? Koperu-Kun and the Company].
 A revised edition was published as one of Shimpen Nippon Shôkokumin Bunko [New Series for Japanese Young Nationals] series in 1956. Another partly revised edition was included in Junia Ban Yoshino Genzaburô Zenshû [The Complete Works of Yoshino Genzaburô for Children] Vol. One in 1967. Iwanami Shoten published a pocket edition in 1982 using the original edition as the standard text.