As the translator notes in his afterword, and Donald Keene and Angela Yiu suggest in quotations used as blurbs on the back cover, Natsume Soseki is one of the giants of 20th century Japanese literature; and probably Ridgeway does not go too far in calling Soseki "the most admired" of all, by the Japanese themselves.
Soseki is best known for his masterful novel "Kokoro," (Note: spoiler follows) depicting an intense relationship between a young man and an older one, known as "Sensei," which ends with the suicide of the latter. The story within the story is of rivalry between two close student-friends for the hand of a beautiful young woman, resulting in the suicide, and lifelong guilt on the part of the "successful" suitor, who is Sensei himself.
Other works universally admired in Japan include "Botchan," about a naive young man and his sometimes comically unhappy exile in Shikoku, and "Sanshiro," depicting another innocent youth who comes to Tokyo to study, grow and be formed by a relationship with yet another Sensei.