The name of Trevanian on the title page--a name as clearly fictitious as anything else in this novel--guarantees "The Summer of Katya" immediate status as a best seller. It was, in fact, edging toward the Top 10 on the Publisher's Weekly list several weeks before its official publication date, following in the tracks of "The Eiger Sanction," "The Loo Sanction," "Shibumi" and "The Main," which is the author's masterpiece--at least under that name.

By making Trevanian books automatic best sellers, the public shows a touching faith in the power of a trademark--a faith that, no matter what kind of book Trevanian has produced this time, it will be worth reading. Trevanian justifies that faith. "Katya" is as well-written as his earlier novels, and once again he has produced a tour de force.

The summer in the title is the last before the outbreak of World War I. The story is set in a village on the French side of the Pyrenees, in the Basque country, where Trevanian has taken his readers before in "Shibumi." It concerns a family of noble origin, strangers in the region, who have rented a decaying manor far out of town, where they live in seclusion, hiding a dark secret. With a few minor changes, the story could be from the pen of Poe or Chateaubriand. Its characters constantly strike poses reminiscent of such authors, though they are living in the last year--the last month--when such poses remained credible in serious European literature.

Except for the Basque local color, there is nothing to connect "Katya" with "Shibumi" on a casual reading (which, we may assume, is all that most books get from most readers). Similarly, there is nothing to connect either of them with "The Main" or all of them with the "Sanction" novels--well-crafted potboilers. The only detectable connections are rather tenuous: a consistently high level of craftsmanship, a certain playfulness of style and a pervasive message that things are not what they seem.

At least these books are linked by a common pseudonym. Not even that clue will be available to guide Trevanian fans to "Rude Tales and Glorious," by Nicholas Seare, which Clarkson N. Potter had originally scheduled for publication around this time but is now holding until September--reportedly because exactly the right kind of paper was not available. "Rude Tales" is a collection of pseudo-Arthurian stories, told with a bawdiness of content and an exuberance of style that would strike envy in the heart of Chaucer or Rabelais. It has, like the Trevanian books and in more concentrated dosage, an underlying obsession with the gap between appearance and reality--not only as a theme of the tales but in their presentation. The chief narrator is a beggar masquerading as Sir Lancelot, and in the telling of the story verse sometimes masquerades as prose.

But the deepest masquerade of all is Trevanian disguised as Nicholas Seare--or Rodney Whitaker disguised as both of them. "Nicholas Seare is a pen name of a well-known, best-selling author," says an ad for "Rude Tales." The indefinite article is precisely chosen; nobody except Whitaker knows how many other pen names he may have used, though this information would certainly interest many Trevanian fans. Under his own name, he wrote "The Language of Film," published by Prentice-Hall and now out of print. In one of the many private jokes that permeate his fiction, Trevanian makes a passing reference to it ("Whitaker, in his lean description of film linguistics . . .") in "The Loo Sanction." As for the choice of his odd nom de plume, the best guess is that it is a tribute to another great, pseudonymous writer: B. Traven, author of "The Treasure of the Sierra Madre."

By any name, he is as versatile and accomplished a fiction technician as any writing today. In "The Summer of Katya," he evokes a world almost as hopelessly lost as that of Arthurian legend, though still close to us in time. As in "Rude Tales," he evokes it in a fair approximation of its own language and style, and he peoples it believably (at least for the moments of reading). The writing is at all times meticulous, superbly controlled and structured with a keen sense of tension, release and climax. "Katya" builds slowly to a final scene that should tell a careful reader, without outside information, that the author is an expert on the language of film. Its characters are relatively few, compared with some of the other Trevanian books, but all are vividly realized, and they draw the reader irresistibly into a story that explores meticulously some of the darker corners of the human soul.