A NONFICTION BOOK seeks to convey information. A picture book must use very few words. A non-fiction picture book, therefore, imposes a special kind of discipline on an author: to present some body of knowledge through a judicious combination of images, verbal and visual. Although the pages are large, they are not plentiful. Even more than many other authors, therefore, the creator of a successful nonfiction picture book must know precisely what it is he wants to convey, and find precisely the right means to convey it. Limited goals, however, by no means imply easy work. The book must appeal to the awakening understanding of a child without offending the sensibilities or the intelligence of the adult who makes the purchase.

Summer Is. . . seeks to present the turning year as a series of sense impressions. Through sensitive examples poetically expressed ("Summer is bare feet and dandelions and roses full on their stems. . . . Winter is lamps lit early and the warmth of home") and comforting, evocative pictures, Zolotow and Bornstein carry the reader through the emotional experience of each season. A plump, motherly woman and a small child in a unisex wardrobe eat watermelon under a shade tree, buy cider at a roadside stand, shovel the front walk, and watch for the first crocuses. Asked one 3-year-old when the book was done, "Can we go there some day?"

City Seen from A to Z is as successful in evoking an emotional response to its subject, a child's-eye-view of everyday Manhattan. This is not a sophisticate's New York, but the city of fire-hydrant showers on the August-hot pavement and grandparents with Old-Country ways. Indeed, this is one of very few children's books in which old people play a natural, pervasive role. Grandparents take young children for walks, stand with them on the beach, buy them ice-cream cones. Ostensibly a simple A-B-C, the book has a wit and sensitivity that transcends the form. Isadora's elegant, perceptive pictures capture small realities of city life. For example, M is for "Music"; a sweet-faced aspiring street kid of 8 or 9 stands proudly with his suitcase-sized portable radio. H is for "Hats"; two small sisters shyly show off their Easter finery. B is for "Beach Ball"; in particular, a multicolored one flying past the head of a fat lady in a two- piece bathing suit in the water at Coney Island. It's too bad that most children in these parts lack the experiences that will make this fine book ring true. But it's a rich introduction to city life, and for any child (or exchild) who knows New York, it has the real flavor of home.

People Working successfully initiates children into one of life's great mysteries: what grown-ups do all day. Well, what they do is bustle through amiable, informative pictures of work in many settings. The pages of this book are, fittingly, very busy, as men and women deliver mail, pick apples, concoct spaghetti sauce, fix teeth, and catch fish. Florian has chosen examples both original and apt. "People work high in the air," constructing high-rises. "People work together" in a symphony orchestra. And there are witty touches that befit the author's background as a New Yorker cartoonist. The TV station where his people work is WORK. The newspaper they print is "Harold's Tribune." No child seeing these confident adults going about their purposeful lives could fail to conclude, as Freud observed, that work is half of a well-lived life.

Parade also more or less succeeds at what it sets out to do; but unfortunately, that is neither terribly significant nor engrossing. It presents the chronology of a parade, from the early-morning street-sweeper that prepares the route, through the arrival of the vendors, the watchers, the bands, and the floats, and finally the return of the street-sweeper to clean up the confetti. But it's not any particular parade, so it lacks the flavor of any real celebration, whether an Inaugural or a small- town Fourth of July. And the pictures, though pretty, don't serve child readers very well; they decorate more than they illustrate. They are vivid and highly sophisticated, but almost too stylized for a small child to make out or respond to.

Some of the smae problems afflict All Year Long. Nancy Tafuri tried to do some of what Zolotow and Bornstein succeed at, all the while saddled with a fatally unwieldy conception. She attempts to teach at the same time both the days of the week and the months of the year. This results in such awkward captions as "Monday in January and February, Tuesday in March," confusing to a child still too young to know that each day comes four times in every month. The pictures are pretty, but only a handful strike an emotional chord. Fireworks over a darkened hill do catch the mystery and glory of the Fourth of July, but this successful picture only enhances the impression of talent misspent on a project incompletely thought out.

I also wish that Lisl Wiel had thought out I, Christopher Columbus more clearly. It is an interesting life of the great explorer, but at once too sophisticated and not sophisticated enough. Children old enough to understand such concepts as going west to reach the east or mistaking the American Indians for inhabitants of the East Indies are too old (at least in their own estimation) to be much taken with a picture book, even one as cheerfully illustrated as this.