In "The Eagle Has Landed," Jack Higgins did the seemingly impossible -- he gave the world some lovable literary Nazis. In "Solo," he goes that trick one better and presents a classy Soviet hit man.

Such sweeping claims need a bit of definition, perhaps. The Germans in "The Eagle Has Landed," which was one of the really distinguished suspense novels of the '70s, were not Nazi political types but members of a special, elite German military group that tried to kidnap Winston Churchill during World War II. In "Solo," John Mikali is not a Russian; he is a Greek-American who finds politics boring but happens to work for the Soviet Union. And he does not work for the KGB, whose professional killers suffer from a lack of class that must be the scandal of the industry. He works for Soviet military intelligence, an altogether superior sort of cloak-and-dagger operation, at least in suspense novels.

One thing is sure, however: Mikali has the kind of class one expects only in a very small elite of professional killers -- those of Trevanian's novels, for example. He is an international superstar concert pianist, who did a hitch in the French Foreign Legion before he began to wow music-lovers and kill occasional victims around the world.

The concert-pianist cover is almost ideal for anyone who wants to kill people on several continents. It gives the perfect pretext for jetting all over the map, and confers on the killer a sort of reverse invisibility; his arrivals and departures are so widely publicized that nobody thinks of him in any context except spotlights and cheering multitudes. A killer is expected to skulk a bit, and headline virtuosos are unable to skulk, aren't they?

(Actually, the skulking opportunities in the trade are nearly ideal; the virtuoso works only a few hours a week, with ample time left over for private pursuits. But the publich doesn't usually think about that.)

There is also the question of personality. Cold, professional killers tend to have a grudge against the world, while virtuoso pianists are, on the whole, a happy, mild-mannered lot who would never dream of killing anyone except perhaps, an occasional music critic. Their emotions have a darker side, but it tends to focus on insecurities and self-doubts rather than violence against others. Their stormier passions are purged regularly -- and profitably -- through the music of such composers as Rachmaninov and Prokofiev. They suffer no economic problems, and they enjoy to a high degree the unmixed admiration of mankind -- even a nonmusical people who respect technical expertise and superb physical conditioning.

So why would a virtuoso pianist become a professional killer? Here Higgins faces the basic technical challenge of this book -- to make his central character credible -- and he does it with the virtuoso technique that one has come to expect of him.

John Mikali is from a wealthy family of shipping magnates whose roots are on the isle of Hydra and whose fortune originated in centuries of piracy and blockade-running. While John is a student at the Paris Conservatoire, his closest friend is killed by a hit-and-run driver whom he recognizes, tracks down and quietly, efficiently assassinates. In his emotional turmoil over the vent, he interrupts his music studies to do a stint in the French Foreign Legion, where his skills as a killer become as polished as his piano-playing. After the loss of Algeriaa, he goes back to the piano. He is not yet 21.

Outside of discouraging an occasional mugger, his combat skills lie dormant until the military junta in Greece assassinates his grandfather -- and then he has a colonel to kill. His undercover activities become known to a Soviet agent who recognizes that he has come to enjoy this sport, and his second career is launched.

In the whole of this colorful second career, Mikali makes only one serious mistake; while escaping from one of his jobs, he accidentally kills the daughter of one of his peers -- Col. Asa Morgan, a British specialist in antiterrorist tactics. One man who became a killer through family loyalty becomes the target of another man driven by the same passion, and the relentless hunt is on, climaxing in a vivid chase scene in the labyrinthine corridors of the Royal Albert Hall with the quarry dressed in white tie and tails.

This is a fitting conclusion to a book that hops across continents, taking the reader to concert halls, luxury hotels, a quiet hideaway on a Greek island and some coloful corners of the London underworld. Because Morgan is working against the Irish Republican Army when he is not chasing Mikali, Higgins is also able to work in a subplot involving Irish terrorist, including a few scenes more vivid than any of Mikali's more professional murders. It is a neat package, fast-moving and well-written, with two central characters who are more credible and sympathetic than the general run of action-suspense heroes. It is not quite the tour de force that "The Eagle Has Landed" was, but it is a thoroughly absorbing story.