"A Soldier of the Great War" is Mark Helprin's third novel, and his best, which is very good indeed.

Helprin, who began publishing short stories in the New Yorker when he was in his 20s, won some literary prizes in his youth. In this novel he realizes his early promise with a mature and engrossing story.In some ways it is a historical novel, the life of Allesandro Giuliani, an Italian born at the end of the 19th century, a soldier in World War I, a horseman and a mountaineer, who is also a professor of aesthetics. But the book transcends its period to speak to the contemporary reader.

Helprin has developed his original and unusual style over time. He is highly imaginative, and in his earlier work strained sometimes to move his readers into a fantastic dream world (as in "A Winter's Tale"). Here his imagination is controlled, but still full of fresh invention.

Helprin is not afraid of long sentences, of interesting digressions, of comments on love and beauty. Yet his story is one of adventure, combat and hardship, filled with remarkable characters, from the mad dwarf Orfeo to Rafi, the mountain-climbing Jew, whom Allesandro befriends.

Most of Helprin's short stories and his last two novels were set in earlier times. In most of them, as well as in this novel, it is possible for a son to love his father, and then in time to love his son. Men and women, too, can be faithful for life.

This is a welcome and refreshing change from most contemporary fiction, yet in setting his books back in time, Helprin is saying in a subtle way that the wars of this century have made love, beauty and moral behavior rare in our world.

"A Soldier of the Great War" begins when Allesandro, an old man, walks a long way with young, illiterate Nicolo and tells him his life story, and how the war and the fascism it spawned completely changed his world.

In the Rome of the early part of this century, when sheep were driven through the streets, a young Italian boy could learn horsemanship from his father, could become a fine marksman and go to the Alps to learn how to climb rocks and glaciers. He could adventure with his friends, yet learn to love art so much that he could travel through the dangers of wartime Germany to see one Raphael painting hanging in a museum in Munich.

Halprin is an original and talented writer; this book deserves a wide audience.