Of all Japanese novelists, Shusaku Endo is the most accessible to Western readers. This is not merely because he spent many years in France and has obviously been influenced by a variety of European writers, but because he is also a Roman Catholic….

Whether we are Christians or not, a heritage of Christianity permeates all our thinking; but that heritage is wholly alien to all but a small section of the Japanese population.

Once again, in When I Whistle, Endo returns to the theme, already used by him in his masterly The Sea and Poison, of human vivisection. (p. 23)

The one flaw of the novel lies in the Iago-like character of Eiichi, whose evil is so calculated and complete that it is difficult to believe in him. Graham Greene, to whom critics like to compare Endo, would have shown some faint illumination of grace even in a heart so dark. Ozu on the other hand—unintellectual, ordinary, decent, hardly understanding his attachment to the memory of his dead school-friend—is a beautiful creation….

In describing Aiko's illness and death, there are moments when Endo seems to escape sentimentality only by a hair's breadth; but each time he withdraws from the edge just in time. There is a terrible sadness in his account of the war years and their humiliating aftermath; and the story of the doomed woman, who has already lost both her child and her husband in the war, is profoundly depressing….

One senses in Endo a profound hatred of change: the beautiful things that are disappearing are not only trees, rivers and old houses but also such intangibles as decency, humanity and idealism. Eiichi, with his destructive egotism, and his efficiently soulless hospital are symbols of a new Japan that frightens and awes the author.

Weaving back and forth in time, this book suffers from none of the feebleness of construction so common in even the best Japanese fiction. Saner than Mishima, closer to us than Kawabata and more universal than Tanizaki, Endo is one of the half-dozen leading novelists of the post-war period. (p. 24)