ROBERT LUDLUM writes spy thrillers the way the rest of us play Scrabble. Ludlum has 25 tiles, with words on each - words like World War II, secret documents, Nazi war treasure, CIA, Vatican, Rio/Buenos Aires, Geneva/Zurich, Berlin, MI-5, Maserati, beautiful blonde, Gestapo, double agent, international banker, false passport. Each year Ludlum chooses half the tiles, face down, and turns them over, arranging them this way and that until some reasonably plausible sequence appears. He then plays them over, on a board whose red and blue squares are maked violence (lots of them), sex (less), doublecross, disguise, assassination, fear of insanity, and so forth. Fill in the details and you have a Ludlum thriller. A CIA agent in a sexual encounter with a disguised beautiful blonde in Moscow? No problem. A chase through Geneva in a Maserati for Nazi war treasure? Viola. When the book is finished, Ludlum takes one tile from "names" and one from "nouns," and thus is born The Scarlatti Inheritance, The Ostermann Weekend, The Matlock Paper, The Gemini Contenders The Chancellor Manuscript and now The Holcroft Covenant.

The Holcroft Covenant is a story of Nazi war treasure, but with a twist: the treasure in this case was accumulated during the war by a small group of high-ranking German officers appalled at Hitler's desecration of humanity; shortly before their deaths they entrust the riches to a Geneva bank to gather interest until their young sons and daughters come to maturity, accept the fortune from the bank and use use it to make amends to the victims of the Holocaust. Thirty years later, the bank reveals the secret covenant to Noel Holcroft, whose mother left her Reichsfinancier husband Heinrich Clausen in 1939, taking their infant Noel to begin a new life in New York, far from Clausen and Hitler. Holcroft, awed by the covenant's revelation that the father he never knew was really a good German, must locate the unsuspecting children of his father's colleagues so that together they can become trustees of the treasure and use it for its noble purpose.

But Holcroft is secretly shawed by die Sonnenkinder, 1650 children of bad Germans who discovered Clausen & Company's convenant back in 1943. The bad Germans spirited the young Sonnenkinder out of Germany in the final days of the war so that they could grow to maturity and power in seemingly innocent lives throughout the world. Now their leaders scheme to use an unwitting Holcroft to gain access to the treasure and so finance the uprising of the Sonnenkinder and the establishment of the Fourth Reich.

This by itself would be middling good stuff for a thriller, but Ludlum is not half finished. Clausen was really a bad Nazi and his covenant, unknown to Noel Holcroft, is a hoax (the clues are all in the first five pages). The future fuhrer is Johann von Tiebolt, die Sonnenkinder's brilliant and malevolent leader, a foreign correspondent for the Manchester Guardian who moonlights as the assassin of the Kennedys, Martin Luther King and others too numerous to mention. Holcroft does not learn of the hoax until dreadfully late in the book, by which time he has to do some furious backpedaling if he is to foil von Tiebolt. And you would underrate Ludlum if you assume that Holcroft will indeed foil von Tiebolt and make the world safe for democracy. A happy ending is not neccessarily one of the squares on Ludlum's Scrabble board.

Ludlum's thrillers tend to have a certain interchangeability, since the same tiles turn up again and again. But here is nothing particularly wrong with that, so long as the reader knows not to expect things he would find in more sophisticated novels - like development or depth of character. The plot is all, and suspense is the only leavening. Ludlum's characters learn and grow with all the suspense is the only leavening. Ludlum's characters learn and grow with all the sublety of an 80-mile-an-hour downshift. This tends to produce a certain number of fourword paragraphs ("An assassin! Oh, God!" or "Who could stop them?" or "Silence. Then footsteps again." and to reply on italics to show realization ("He was trading off nothing!" or "There could be no association at all. MI-Five had followed him.") but what of it? The prose fits and the plots are as convoluted as anyone could wish, with as many twists and turns as, well, as a chase through Geneva in a Maserati.

To follow the plot takes some doing. One must keep track of half a dozen major characters and figure out what they know and when they knew it, otherwise the various sleuthings, plottings and killings lose much of their pizzazz. Ludlum fans surely know what to expect for their $10.95. First-time readers can save several dollars by skipping Holcroft and picking up one of Ludlum's name-and-a-noun thrillers in paperback.

All the tiles are there, too.