Roger Caras, an ABC News correspondent who reports on animals, is a dog lover with a knowledge of them gleaned over years of study. He has written a book that should be a must for anyone interested in our canine friends.

"A Celebration of Dogs" is not designed to be an authoritative book for the person trying to decide on a particular breed, but rather is a celebration of all dogs by an author who clearly loves them.

His book is crammed with facts and therefore is not exactly light reading. But although one has to concentrate, it is well worth the effort. This reviewer, active in professional dog circles for more than 40 years, has learned a great deal by a perusal of the chapters.

It is astonishing to learn that about 52 percent of American families have one or more dogs. Or that we in the United States spend roughly $6 billion a year on dog food--right on a par with some of our biggest industries. And that the dog show put on annually by the Westminster Kennel Club at Madison Square Garden is the second oldest continuous sporting event in the United States--outranked by only one year by the Kentucky Derby.

There are many breeds of dogs. The American Kennel Club recognizes 130. The United Kennel Club registers a few more, but the latter organization does not have nearly the weight or prestige of the AKC. There are still many more breeds throughout the world that will probably eventually come to our shores, and Caras' chapter "Miscellaneous Breeds and Other Dogs" tells about some of those not yet in a position strong enough numerically or in terms of breeding records to be recognized by the AKC.

He tells us about the fascinating shar-pei, which he aptly describes as a "miniature hippopotamus with loose fitting panty hose." Wrinkles galore, ugly to some, but people can be found who think it a "beautiful" breed.

He also tells about the border collie, one of the oldest and most intelligent of all breeds. While some groups push for AKC recognition, border collie people don't want AKC registration privileges. They fear that fanciers not interested in the working ability of the dogs will ruin the animals' instinct for herding sheep. Fanciers of a hunting breed, the Jack Russell terrier, take the same stand.

Chapters on the seven groups defined by the AKC--Sporting, Hound, Terrier, Toy, Non-Sporting, Working and Herding--are full of anecdotes and interesting sidelights on the various and many breeds Caras has known. He relates that Chinese emperors employed human wet nurses for the favorite lap or sleeve dogs, perhaps murdering infants to ensure adequate milk for the pets.

The chapter on dog shows is a must. To the uninitiated, a dog show is pure bedlam--rings all over the grounds where various breeds are being paraded before authorities, people running between rings, loudspeakers blaring. Caras makes amusing sense of it all.

Perhaps intentionally, Caras does not wax too sentimental about dogs. It is, of course, too much to expect that he could refrain from quoting the Missouri lawyer's famous 19th-century paean to dogs at the trial of a dog killer: "A man's dog stands by him in prosperity and poverty, in health and sickness. He will sleep on the cold ground, when the wintry winds blow and the snow drives fiercely, if only he can be near his master's side. He will kiss the hand that has no food to offer, he will lick the wounds and sores that come in encounter with the roughness of the world. He guards the sleep of a pauper as if he were a prince. When all other friends desert, he remains."

There is so much more here. Caras' book is enchanting, engrossing, amusing, written by a writer of stature who knows his subject inside out.