You needn't tell a gull by its cover.

That's the broad message in the new book "Gulls Simplified, a Comparative Approach to Identification."

Plumage is a major factor in historic and most contemporary ID guidance for this large family of birds. Plumage is highly variable, however. For many species it depends on season, age of the bird, and molt pattern. Co-author Pete Dunne says that plumage-based decisions compound the complexity of the task.

Dunne makes a strong case for ignoring feathers, focusing instead on shape and profile. Birds are not shapechangers. You can make identification less complex (and less argumentative) by comparing physical characteristics, say Dunne and co-author Kevin T. Karlson.

Dunne says that he was the perfect person to write this book because while an experienced birder, he harbors no "deep fascination with gulls."

His ID method "hinges mostly on traits easily notes in the field," which are, he says, size, shape, behavior, structural features, habitat, distribution, range, and direct comparative assessment.

In other words, he works gull identification as he would for any other family of birds. Makes sense to me.

Dunne is a lively writer of long experience, both in the field and at the keyboard. Karlson's photos are perfect. You will see gulls displaying the varied shades of brown, gray, and white that come (and go) with age. Don't be distracted. Pay attention to the authors' instructions.

The maps are good. My sole quibble is the size of the type and choice of sans serif face. Serif type — letters with feet and caps — is easier to read, I think. The size in this case, I am guessing, was determined by the wealth of text. Books can only be so large. Lines are well-spaced, easing your read. Don't let my idiosyncrasies put you off.

Princeton University Press is publishing this book, to be available in mid-November. It is soft-bound with durable cover. Its 208 pages include a photo quiz, a test on your new knowledge.

In the production credits accompanying publication information in the front of the book the names of editors, designers, production supervisor, and copyeditor are given, as should be. They, after all, have a great deal to do with you successfully and happily using this book.

Cover design was by Carmina Alvarez Geffen. Her choice and use of the cover photo is beautiful.

Copy editor was Laurel Anderson. I'll bet she knows a lot more about gulls now than when she began this project. You can follow her lead.