"HE'S STRONG as a man and weighs as much. He's fast, he's got teeth like a Roto-tiller, and he's not afraid of anything that breathes."

That's Metzger's dog we're talking about, and Metzger is Dr. Henry Metzger, and he's a cat. Metzger and his dog are two of the most endearing animals this side of Toad Hall, but this is not an animal story we've got here. It's a thriller, and it's a beaut, and there's not one wrong word in it.

Dr. Henry Metzger belongs to--make that lives with--a chap named Chinese Gordon, and we first meet them both when Chinese senses the presence of a gang of intruders in his pitch- dark abode. He routs them by dropping Dr. Henry Metzger upon the head of one of their number. Chinese Gordon (who does not seem to be Chinese, and may not be Gordon, and it doesn't matter) has a terrific girlfriend named Margaret and two good buddies named Kepler and Immelmann, and they all team up to liberate a million dollars' worth of confiscated cocaine from a university science lab. On the way out, Chinese knocks out a parking lot kiosk with a few rounds from his home-made anti-aircraft cannon.

And away we go. In the course of the burglary, Chinese also acquires (in a perfectly plausible fashion) a manuscript detailing government-financed research for the subdivision and social devastation of various South and Central American nations. This material would prove a huge embarrassment to the Central Intelligence Agency. Chinese has just sold the rescued cocaine back to its unrightful owner; enterprising lad that he is, he determines to sell the manuscript to the CIA. The Company, in turn, promptly closes the barn door by assassinating the professor who did all the research. Now they commence hatching schemes to entrap what they assume to be a new and dangerous band of foreign terrorists, hoping to recover the manuscript in the process. (The counter-kidnapping of a delegation of Soviet visitors is just one of the Company's ploys, and by no means the most remarkable.)

Metzger's Dog is Thomas Perry's second novel. His first, The Butcher's Boy, richly deserved its Edgar award as Best First Novel of 1982. When I read The Butcher's Boy I had a little trouble believing it was indeed a first novel, not so much because of its quality-- first novels are often excellent--but because of the burnished professionalism evident on every page.

This book is even better. Understand, please, that Perry has not written a comedy or spoof. His thriller never ceases to be taut and, well, thrilling. His scenes of violence, while never excessive, are equal to the occasion, even as Chinese's cannon is up to the job of wasting the parking kiosk. But the book is riotously funny in spots because its characters are witty and wry and their perceptions are funny.

When Chinese is piloting the coke-laden van away from the scene of the first crime, hoping to avoid detection from police helicopters, he switches from one road to another until--

"'I see your plan,' said Kepler. 'You're going to keep turning onto smaller and smaller roads until finally the road and everything on it just disappears.'"

Marvelous characters abound. Porterfield, the Company's man on the case, is a matter- of-fact spook nicknamed "The Angel of Death" by his confreres. He earns the nickname, yet he manages to be a sympathetic character throughout. He's been married to the same woman for 30 years, and their continuing love affair is both sweet and convincing.

Jorge Grijalvas, who buys back the cocaine from Chinese Gordon, has a certificate in his office from the Chamber of Commerce "for his efforts in renovating low-income housing in the Los Angeles Barrio" and a black plastic sign proclaiming his membership in the Better Business Bureau. Immelmann calls all his girlfriends "Little Lady" or "Sunshine" because it's easier than remembering their names.

Perry has tucked imagination and ingenuity sufficient for 10 books into Metzger's Dog. When Chinese and his merry men swipe the coke, they pose as repairmen; each wears a gray work shirt with a patch sewn on saying "Dave." Immelmann stole all three shirts from a Laundromat dryer. Later Margaret, decked out as a hotdog vendor, passes a note and payoff to Grijalvas during a baseball game, doing so as neatly as a magician forcing a card.

And when Chinese modifies a CIA case study and shuts down the entire city of Los Angeles--perfectly, plausibly, and with a cast of four--one is struck dumb with admiration. It could happen here, I thought--and found myself rather hoping it would.

Metzger's Dog reminded me now and then of Donald E. Westlake and Ross Thomas at their best, of Jimmy Breslin and Vincent Patrick without the New York accent. Thomas Perry's writing is clean and crisp and lively, his California sets vivid, his characters at once wacky and toughminded, his plot a wondrous construction. I read Metzger's Dog at one sitting, taking my time and savoring every word, and there was not a moment when I'd have rather been doing something else.