"Because children have abounding vitality, because they are in spirit fierce and free, therefore they want things repeated and unchanged. They always say, "Do it again"; and the grown-up person does it again until he is nearly dead. For grown-up people are not strong enough to exult in monotony. But perhaps God is strong enough to exult in monotony. It is possible that God says every morning, "Do it again" to the sun; and every evening, "Do it again" to the moon. It may not be automatic necessity that makes all daisies alike; it may be that God makes every daisy separately, but has never got tired of making them. It may be that He has the eternal appetite of infancy; for we have sinned and grown old, and our Father is younger than we."
--- G.K. Chesterton, Orthodoxy

Orthodoxy (1908) is a book by G. K. Chesterton that has become a classic of Christian apologetics. Chesterton considered this book a companion to his other work, Heretics. In the book's preface Chesterton states the purpose is to "attempt an explanation, not of whether the Christian faith can be believed, but of how he personally has come to believe it." In it, Chesterton presents an original view of Christian religion. He sees it as the answer to natural human needs, the "answer to a riddle" in his own words, and not simply as an arbitrary truth received from somewhere outside the boundaries of human experience.

The book was written when Chesterton was an Anglican. He converted to Catholicism 14 years later. The title, Orthodoxy, is meant to avoid such sectarian questions.