What is little more than two inches wide, less than three inches long, slipcased and bound in snakeskin, inlaid with seed pearls and a two-point diamond, and retails for $550?

Why, a book, of course. And not just any book. It's a 64-page volume of previously unpublished 1930s Harper's Bazaar cover paintings by the renowned Art Deco designer and illustrator Erte', who celebrated his 92nd birthday last Friday and who hand-signed the deluxe versions of this miniature book. (For those who might bridle at spending $500 on such whimsy, a simple silk-bound copy can be had for a mere $85.) The paintings, 44 of them in all, are maquettes, or studies for larger pieces. These maquettes, the originals of which are not much larger than the book itself, were submitted to the editor of Harper's for the selection of an appropriate cover, but only two were actually used.

Erte' (the well-known signature is simply the acronym of his initials spoken in French) was born Romain de Tirtoff in St. Petersburg, Russia, in 1892. He moved to Paris in 1912 to study art but wound up a fashion designer and, over the next 60 years, created clothes for the rich and famous, kings and queens, and such theatrical personalities as Mata Hari, Lillian Gish and the Ziegfeld girls. Though he never achieved the status of "great artist," and probably never intended to, Erte' nonetheless became the style-setting paradigm of the period that all those who appreciate that sort of thing recognize as Art Deco. His brilliantly colored, often garish illustrations for Harper's, spanning some 17 years, recall the roaring good humor of Robert Benchley, the cruel wit of Evelyn Waugh and the empty elegance of "The Great Gatsby." They don't quite beckon, but they are intriguing.

Though cultural esthetics have changed considerably since his heyday, Erte' enjoyed something of a reemergence in the 1970s as one of the high priests of Deco, and his original paintings and drawings now command quite respectable sums. So perhaps it is fitting that his attainment of quite a respectable age be commemorated in such an elegant, expensive way. The book is rather precious, but, then, so is the art.

The publication is the work of Rebecca Bingham, founder of Rebecca Press, a concern that publishes miniature books exclusively, a tradition dating back to the Middle Ages. Since the establishment of Rebecca Press in 1980, Bingham has published seven tiny titles, including "The Legend of Sleepy Hollow," "Nonsense Botany," featuring the drawings of Edward Lear, and "Edna St. Millay: Sonnets and A Few Poems." They sell throughout the world to collectors of miniature books, who pay enormous amounts of money to satiate their desire to own something that is as close as writing gets to being jewelry.

"Arthur Houghton Jr., who endowed the Harvard Library, owned over a thousand of them," says Bingham. "And Stanley Marcus, part owner of Nieman-Marcus, is an avid collector, too. I have buyers in Australia, Europe, Japan, and a large contingency on the West Coast. There's quite a roster of collectors.

"The books are expensive because they are so labor-intensive. They are so small that the signatures page sections have to be folded and bound by hand. They won't fit on the usual machines, so the binding costs are a good deal higher. And when you're working that small, if the print is off a sixteenth of an inch, the whole page is crooked.

"I started doing the books in 1980 -- I think it was my 'thirties crisis.' I needed something creative to do. The Erte' book is the first full-color book I've done, and it's definitely the smallest book of his work that has ever come out. I found the maquettes in London two years ago and, as they were already so small, they seemed the perfect subject for a book. I've always admired Erte' -- ever since I first became acquainted with his work in the '70s -- and wanted to publish them anyway." And what does Erte' think of the book?

"He thinks it's quite lovely," says Salome Estorick, with her husband Erte''s sole representatives in international dealings from their base in London. "So many books are out about him, you know. It seemed to make sense to do one on the smallest works that he has ever done. But," she confides, "it is a little expensive, isn't it?"