ByJane Stewart Spitzer, After 10 years at CBS Inc., Jane Stewart Spitzer now reviews popular fiction for the Monitor. ''The Danger,'' Dick Francis's latest suspense novel, has all the hallmarks of a typical Francis yarn, yet it is his most untypical. His first 19 novels dealt almost exclusively with the world of horse racing, a world that Francis, a former jockey, knows well. In the next three, Francis began moving in new directions, combining horse racing with photography in ''Reflex,'' with computer programming in ''Twice Shy,'' and with investment banking in ''Banker.'' In ''The Danger,'' horse racing provides a mere backdrop to the main action - kidnapping. Andrew Douglas is an operative for Liberty Market Ltd., an English firm whose business is helping actual and potential kidnap victims. He knows nothing about horses, but in other aspects Andrew is a typical Francis hero. His looks - brown hair, regular features, and medium height - are both ordinary and quietly attractive. He is an intelligent loner who combines pragmatism with idealism and sensitivity with toughness. Andrew is also uninvolved emotionally until he gets to know Alessia Cenci, a female jockey and a kidnap victim. It is an asset in Andrew's business to be uninvolved, and he works at it. An emotional entanglement would cost him the perspective that enables him to do his job well. Several of the other characters comment on Andrew's cool aloofness, but the reactions he gets from two of the kidnap victims he helps rescue, Alessia and the baby son of a race horse owner, indicate that Andrew also has hidden depths of warmth and tenderness. Unfortunately for the reader, these depths are only hinted at. Because Andrew is not as fully developed a character as Francis's heroes usually are, it was difficult for me to really like Andrew and feel as involved with him as I usually do with a Dick Francis hero. There are differences between ''The Danger,'' and Francis's previous novels in plot and style as well. He provides great chunks of information about the psychology and techniques of kidnapping and the effects on the victims and their families. This information, although interesting and important to the plot, does slow things, and the action takes longer than usual to get under way. The kidnapping information is delivered in a somewhat perfunctory manner and lacks the inspired enthusiasm that Francis can bring to the most mundane aspects of horse racing. Once under way, however, the plot is exciting and leads eventually to the usual confrontation between the hero and villain, in this case, the kidnapper. A Francis hero usually gets beaten up at least once. Andrew doesn't; he gets kidnapped instead. In the end, these differences are relatively minor points. Dick Francis is clearly moving away from his horse racing formula, yet his basic style remains the same. Unlike some other popular authors who try unsuccessfully to change, Francis seems to be one author who can expand in new directions and still write a novel that maintains his reputation.