The story recounts the experiences of Joey, a horse bought by the Army for service in World War I in France and the attempts of 15-year-old Albert, his previous owner, to bring him safely home.

The novel is often considered one of Morpurgo's best works, and its success spawned a sequel titled Farm Boy, which was published in October 1997.

After meeting a World War I veteran, Wilfred Ellis, who drank in his local pub at Iddesleigh and who had been in the Devon Yeomanry working with horses, Morpurgo began to think of telling the story of the universal suffering of the Great War through a horse's viewpoint, but was unsure that he could do it.

[4] Interviewed by Fi Glover on Saturday Live on BBC Radio 4 in December 2010, Morpurgo recounted the event that convinced him he could write the book: One of the kids who came to the farm from Birmingham, a boy called Billy, the teachers warned me that he had a stammer and told me not to ask him direct questions because it would terrify him if he had to be made to speak because he doesn’t speak...I came in the last evening into the yard behind this big Victorian house where they all live, and there he was, Billy, standing in his slippers by the stable door and the lantern above his head, talking.

And the horse, Hebe, had her head just over the top of the stable, and she was listening; that’s what I noticed, that the ears were going, and I knew she knew that she had to stay there whilst this went on, because this kid wanted to talk, and the horse wanted to listen—this was a two way thing...I went and got the teachers, and brought them up through the vegetable garden, and we stood there in the shadows, and we listened to Billy talking, and they were completely amazed how this child who couldn’t get a word out—the words were simply flowing.

"[6][7] The painting was by F. W. Reed and was dated 1917, and showed a British cavalry charge on German lines, with horses entangled in barbed wire.

While with the Narracotts, Joey also meets Zoey, a horse who was a source of comfort to him, and whose name partially inspired his.

Joey is trained for cavalry service by Corporal Perkins, and Captain James Nicholls is his original rider, leading a unit of mounted infantry.

The Germans allow Emilie and her grandfather, who live in a farm near the front lines, to care for Joey and Topthorn.

After seeing an Allied tank for the first time, Joey runs in terror and is wounded by barbed wire before breaking free.

At the end of the war, Major Martin announces that they will auction off all the horses, despite the protests of Sergeant Thunder and the rest of the soldiers.

[10] In February 2010 it was revealed that the play would transfer to Broadway in New York City, and has since been seen in separate and touring productions in Canada, Australia, South Africa, the Netherlands, and Japan, as well as translations into German (Gefährten) and Chinese (战马).

[11] In May 2010, it was announced Steven Spielberg would direct the movie adaptation with Richard Curtis and Lee Hall writing the screenplay.

[16] It featured Timothy Spall starring as the voice of Albert, Brenda Blethyn as Mother and Bob Hoskins as Sergeant Thunder.

A Welsh version of the novel, adapted by Casia Wiliam and titled Ceffyl Rhyfel, was published by Gwasg Carreg Gwalch in 2010.