G. K. Chesterton's Orthodoxy is an account of how he came to hold Christian orthodox beliefs. By the term "orthodoxy" (the lowercase 'o'), he is not referring to a branch or denomination of the Church, but rather ". . . the Apostles' Creed, as understood by everybody calling himself Christian until a very short time ago and the general historic conduct of those who held such a creed."
I happened to read Orthodoxy during or just after my 20th cent. Brit. History course, which included references to H. G. Wells, George Bernard Shaw, and other people of letters. There was not one mention of Chesterton, despite his friendship with both Wells and Shaw; he does not fit neatly into the agenda presented in such a history course. And this, even though Orthodoxy does not pose as an opposing argument to atheism or "unorthodoxy" - Chesterton's focus seems more to explain than proselytize.
In this very fact, Orthodoxy is made more persuasive than it might otherwise have been. I think it is best read as simply one man's reasons for his Christian faith, and as such there is a lot that even non-Christians can gain from reading it. Apart from answering the question of "Why do you believe?", Chesterton expresses some powerful points of his philosophy in really excellent writing, using his classic humorous wit and analogies. His style does read like a rambling college lecture, but in a good way, especially for those of us who dread the typical "boring lecture" format of nonfiction.
Interestingly, Chesterton, like C. S. Lewis, did not embrace Christianity until adulthood. His answer to "why believe?" is based greatly on his own experience and reasoning, which may or may not convince non-Christians (but again, the book is more an autobiography than anything else). Personally, I felt like I should have read this a long time ago, not only because it is a Christian classic, but because it earned that status. Chesterton gives a fascinating perspective on topics like logic, reason, and miracles - topics that are not always easy to dissect. This is the sort of book I would re-read every year to fully analyze, but even on the first reading, I found that so much of my own Christian "philosophy" had already been put into solidified words in Orthodoxy.
The Apostles' Creed
I BELIEVE in God the Father Almighty, Maker of heaven and earth:
And in Jesus Christ his only Son our Lord: Who was conceived by the Holy Ghost, Born of the Virgin Mary: Suffered under Pontius Pilate, Was crucified, dead, and buried: He descended into hell; The third day he rose again from the dead: He ascended into heaven, And sitteth on the right hand of God the Father Almighty: From thence he shall come to judge the quick and the dead.
I believe in the Holy Ghost: The holy Catholic Church; The Communion of Saints: The Forgiveness of sins: The Resurrection of the body: And the Life everlasting. Amen.