Carl Purcell is a world-class travel photographer whose pictures and free-lance articles have been widely published in newspapers and magazines. He teaches and lectures about photography, has filmed documentary motion pictures for the Agency for International Development, and currently writes a column for Popular Photography magazine while serving as chief of media services for the public affairs office of the National Oceanic and Atmospheric Administration.

The Bethesda resident, who sold some of his first free-lance travel features to The Post's Travel section years ago and whose photos or story/picture packages appear here from time to time, now has written and illustrated the best practical guide for the travel photographer I've seen.

Whether you have a professional photographic career in mind, are a travel writer with a camera who needs to learn how to illustrate your articles with pictures a travel editor will buy, or merely want to be able to bring back better snapshots or slides from your vacation trips -- this basic guide explains how to compose and expose creatively without resorting to complicated technical mumbo-jumbo.

In an uncluttered conversational style, the book (subtitled "A Professional's Trade Secrets on Equipment, Techniques and Touring") manages to impart a great amount of no-nonsense, useful advice in what is actually a relatively slim volume with a page size of approximately 7 1/2 by 9 1/2 inches.

It is a "picture book," though not one of those gaudy coffee table-type tomes meant to be gift-wrapped at Christmas time, perused swiftly, and then filed away on a shelf. But that is not to infer that the guide does not please the eye, too. The excellent full-color photographs (all by Purcell) were beautifully printed (in Italy) on glossy stock, and they compliment the text perfectly by not only showing what the author means but proving he has indeed mastered the medium in which he gives instruction.

Purcell, who has toted his camera case more than 2 million miles to expose thousands of rolls of film in more than 70 countries, still looks forward "to each new trip with a sense of excitement, a feeling of anticipation. I try not only to discover new places, but new ways of seeing things."

In chapters that run the gamut from "Equipment and Film" to "Breaking the People Barrier" to "The Art of Photographing Art," in Part I, he transmits his knowledge and enthusiasm. In Part II, he offers miniguides to seeing and photographing 12 major tourist destinations around the world. In Part III, there is a brief look at slide shows, movies and careers in photography.

Purcell carefully -- and quite correctly -- cautions beginners that it is very difficult for the unknown travel photographer to market his pictures, warning " . . . the competition is very keen." He points out that "one very important skill . . . is the ability to write and combine words effectively . . . If you have a well-written story to go along with your pictures of Spain, you have a much better chance of selling those pictures."

But, curiously, in this volume he totally ignores newspaper travel sections -- probably the most accessible (though admittedly not very lucrative) "first" market for the travel photographer who can write an acceptable travel article and thirsts for a "byline" and publication experience.