We who've been reading John le Carre for 10 or 20 or 25 years - depending, of course, upon which best-selling novel first drew us in - share an unshakeable conviction: We're certain we're on the unsanctioned receiving end of inside information about the shadow-world of international espionage. "This," we say, "must be how it really is."

"The Secret Pilgrim" only adds fuel to the fire of our belief. And for those who've never sampled such fare as "The Spy Who Came in From the Cold," "Tinker, Tailor, Soldier, Spy" or "A Perfect Spy," this latest le Carre novel offers an excellent and entertaining introduction to his political and moral labyrinth.For "The Secret Pilgrim," in Chaucer's "Canterbury" tradition (hence the title?), regales us with tales unmasking four generations of Secret Service "history" ( . . . a la le Carre) and personalities, but in particular the life and insights of last-nameless Ned, Barley Blair's chief in "The Russia House." These are Ned's memoirs - a fictional autobiography that would be a legal impossibility under Britain's real-life Official Secrets Act.

Early on, Ned says that old watchers (surveillance specialists) "are famous for their moralising - and with reason. First they watch, later they think." As "The Secret Pilgrim" shows, Ned's proved quite the watcher . . . and has entered his thinking stage.

Because this is a one-volume, 30-year Secret Service chronicle, Ned's reminiscences recall a host of familiar le Carre characters, including the devastatingly efficient traitor Bill Haydon, smaller fry like Toby Esterhase and Peter Guillam, and most of all the legendary George Smiley.

In fact, Smiley's benevolent, if sometimes melancholy, spirit hovers over the book, even haunting the dedication, which is to actor Alec Guinness, who portrayed the great spycatcher in two TV miniseries. Ned's stories spill forth after a visit by the tubby, bespectacled Smiley to Sarratt, the Service's "spy nursery"; Smiley's lecture and subsequent fireside chat, sprinkled throughout the book, provide the line upon which Ned hangs his memory-laden laundry, and his qualms about the life he's led.

The manipulation of others can smother your own better natures, Smiley warns the incipient agents at Sarratt - in words that go to the heart of Ned's ruminations. " `By being all things to all spies, one does rather run the risk of becoming nothing to oneself,' he confessed sadly. `Please don't ever imagine you'll be unscathed by the methods you use.' "

As usual, "The Secret Pilgrim," rife with techniques and colorful jargon, verges on a spycraft primer. We read about watchers and lamplighters, joes and moles, the Circus and Moscow Centre, dead-letter boxes and safe houses, listening stations and escape lines. And Ned's travels take us to many of the espionage capitals of the world: Berlin, Hamburg, Zurich, Bangkok and Beirut, as well as London.

But more importantly, we're introduced to a new gallery of fictional characters who are truly characters, as well as their cons, crusades, bungles, betrayals, illusions and disillusionments.

Chief among the cast are Ben Arvo Cavendish, Ned's flawed first friend in the Service, and Ben's German cousin Stephanie; the Middle Eastern voluptuary-prince code-named Fat Boy; sea-going spy Captain Brandt, and Bella, the seductive innocent; Teodor, the ineffectual Hungarian professor-spy, and his cohort Latzi; the half-mad defrocked priest and lapsed spy Hansen; Sgt. Major Arthur Wilfred Hawthorne, who didn't deserve a son like Ken; and Sir Arthur Joyston Bradshaw, a remorseless symbol of institutionalized evil.

Smiley once quoted Horace Walpole to him, Ned says: "This world is a comedy to those that think . . . , a tragedy to those that feel" - an observation applicable to many of the stories Ned tells.

One major segment of the novel may startle those broadly familiar with le Carre's work. The story of the eccentric cipher clerk Cyril Frewin, although much different in approach and tone, echoes the plot of the writer's first novel, 1961's "Call for the Dead," which introduced us to George Smiley. The new tale's well told, but the hint of self-"plagiarism" is vaguely troubling.

Unless, of course, you're willing to see such recycling as a recurring le Carre motif.