The Good Soldier

The Good Soldier by English novelist Ford Madox Ford, is set just before World War I and chronicles the tragedy of Edward Ashburnham, the soldier to whom the title refers, and his own seemingly perfect marriage and that of two American friends. The novel was loosely based on two incidents of adultery and on Ford's messy personal life.
The story is narrated by the character John Dowell, half of one of the couples whose dissolving relationships form the subject of the novel. Dowell tells the stories of those dissolutions as well as the deaths of three characters and the madness of a fourth, in a rambling, non-chronological fashion that leaves gaps for the reader to fill. This literary technique forms part of Ford's pioneering view of literary impressionism. Ford employs the device of the unreliable narrator to great effect as the main character gradually reveals a version of events that is quite different from what the introduction leads the reader to believe.
The novel's original title was The Saddest Story, but after the onset of World War I, the publishers asked Ford for a new title. Ford suggested (sarcastically) The Good Soldier, and the name stuck.
The novel opens with the famous line, "This is the saddest story I have ever heard." Dowell explains that for nine years he, his wife Florence and their friends Captain Edward Ashburnham (the "good soldier" of the book's title) and his wife Leonora had an ostensibly normal friendship while Edward and Florence sought treatment for their heart ailments at a spa in Nauheim, Germany.
As it turns out, nothing in the relationships or in the characters is as it first seems. Florence's heart ailment is a fiction she perpetrated on John to force them to stay in Europe so that she could continue her affair with an American thug named Jimmy. Edward and Leonora have a loveless, imbalanced marriage broken by his constant infidelities (both of body and heart) and Leonora's attempts to control Edward's affairs (both financial and romantic). Dowell is a fool and is coming to realize how much of a fool he is, as Florence and Edward had an affair under his nose for nine years without John knowing until Florence was dead.