HOT MONEY By Dick Francis Putnam. 324 pp. $17.95

DICK FRANCIS' mysteries have been published every spring for more than 20 years. They come out in England the previous fall and many of his fans just can't wait those extra few months. Winter travelers last year returned to Washington loaded down with British editions of Hot Money. Soon the word was out among aficionados: "A good Francis."

And good it is, up there with Whip Hand and Forfeit. It is awesome how this 67-year-old former steeplechase jockey (he rode for the Queen Mother until 1957) produces an annual novel of unrivalled consistency and craft. Each one explores a new area of knowledge -- ranging from artificial limbs to wine-making -- that becomes part of the fabric of the story.

At the center of Francis' 26th thriller are a five-times-married international gold speculator, Malcolm Pembroke, and Ian, his son by his second wife. Ian is an amateur jockey with dreams of turning professional.

Francis once said that his heroes "are the sort of chaps I'd like to meet" and Ian is exactly the kind of young man most of us would love to meet: independent yet responsible, kind yet courageous, full of the moral fiber essential to the kind of chap Dick Francis admires.

So gold bullion trading (at which Malcolm is spectacularly successful) and steeplechase riding are the setting for Hot Money and they make a sexy combination. When Malcolm gets interested in his son's avocation, the two come satisfyingly together. Money is a more accessible central gimmick to most readers than the rather technical plastic firearms or humane killing devices that worked less successfully in last year's Bolt. Spare gold is also very handy in the horse racing business.

The Pembrokes are not a large and happy family. In fact, they could be the Medici in modern dress. Malcolm's riches have in different ways distorted the lives of his children and their spouses. Ian, a personable bachelor with the usual Franciscan reluctance to commit himself to a serious relationship, is unexpectedly presented with a double task: to keep his father from being murdered and to discover which of his siblings or relatives may have been behind the near-miss car accident or the home-made bomb that destroyed the family home.

As his five marriages might indicate, Malcolm was no boy's dream father. He quarreled violently with Ian over his fifth wife, but even before that Ian tells us, "In a totally confused chaotic upbringing I'd spent scattered unhappy periods with my bitter mother but had mostly been passed from wife to wife in my father's house as part of the furniture or fittings, treated by him throughout with the same random but genuine affection he gave to his dogs."

Despite this inauspicious history, affection and trust reawakens between Ian and his father, haltingly with setbacks, as they are drawn together by danger. "It struck me that he really needed to hear me say I loved him, so although he might scoff at the actual words, and despite the conditioned inhibitions of my upbringing, I said, feeling that desperate situations needed desperate remedies, "You're a great father . . . and . . . er . . . I love you." Ian's handling of the shortcomings and problems of his seven half-siblings is enviably laced with compassion and understanding.

TO HANDLE this large and intertwined cast of characters without thoroughly confusing his readers, Francis uses a tried and true technique: he introduces a depressed but highly professional private detective by the name of Norman West to investigate the movements and circumstances of everyone in the Pembroke family. West's flat but conscientious reports to Ian fill in many necessary details and his occasional asides provide a wonderful deadpan viewpoint, taking us briefly outside the family. Of Mrs. Ursula Pembroke, the wife of one of Ian's half brothers, he reports "Mrs. U unhappy woman but wouldn't unbutton. Loyal. Any wife of Mr. G likely to be unhappy (my opinion). . . . Does she believe killing Mr. Pembroke could solve her Problems? Does she believe if Mr. G. Becomes richer it will make things right? I could tell her it won't. End of inquiry."

Best-selling suspense fiction relies on many different elements to creep into the hearts and pocketbooks of readers. Sex and violence are standards -- some of the latter but not much of the former in Francis -- but what is unusual about his immense appeal is that all his books are skilful, elegant variations on a theme of horses and heroism. But they are no more repetitious or monotonous than are a set of Bach variations. We care about his heroes because they are worth caring about. (I'd definitely like to have Ian Pembroke on my side in a crisis.) They represent the best in human nature while struggling convincingly with their own shortcomings and weaknesses. They are never too perfect to identify with and don't win all their races.

Brigitte Weeks is the editor of Book World.