What furniture style is in this year? Well, that depends on what press release you read.

"The overwhelming decorative preference of today's `baby boomers' is traditional.""Country decorating is our most popular style today."

"Shaker furniture is the hottest style on the market today."

Before jumping to conclusions, realize that no ONE style is in this year. The fact is, decorating styles are much more eclectic now than they have ever been.

However, problems easily crop up when mixing furniture styles. That's because many people don't have the vaguest idea about which style is which. They don't know the difference between traditional, provincial and contemporary furniture; or styles from England, France and America.

Traditional styles were favored by kings and wealthy patrons. They were named after reigning sovereigns or after historical designations of an era, for an artisan or a designer.

Provincial styles were colonial interpretations of traditional influences. Colonial craftsmen used simple ornamentation native to their localities. They also injected their own creative ideas. They were named for geographic areas and for the people who first produced them.

Contemporary styles embrace more recent, fresh styles where lines are generally crisp and shapes simple. But these characteristics are altered by the particular style of each designer.

For years, mixing styles was definitely frowned upon. But as designers became more daring, they found that a piece of traditional French furniture made a "unique, elegant statement" when placed in a contemporary setting. And they were surprised to find that Country French and English Cottage styles worked well with Early American period furniture.

Some periods and styles are compatible; others are not. For example, a country pine hutch doesn't work next to a Queen Anne chair.

According to Tina Lee, director of Sheffield School of Interior Design, successfully mixing period furniture requires "following the same basic rules of color, scale, mood and harmony that apply to all decorating."

If you feel uncomfortable about mixing period furniture, perhaps you should contact a professional decorator. They'll give you excellent advice. But let them know from the start that you want a decorating statement that reflects your personality, and not theirs.

Although people are mixing furniture, they still have preferences as far as periods and styles are concerned.

Some prefer antique furniture. In fact, a number of celebrities and other wealthy people are currently battling over Shaker furniture, especially pieces made between 1826 and 1850. Not only are these pieces functional, handsome and well-crafted, they are stripped of any decorative detail.

In auctions last year, a long trestle table brought $94,600, and a chest of six small drawers over six larger ones went for $99,000. And $33,000 was paid for an 1830 birch rocking chair.

But that's enough about the rich and the famous. What about the rest of us?

Our tastes run the gamut between early traditional to ultramodern. Name a style - any style - and you'll find quite a following.

However, more and more people want the elegance of traditional furniture as well as 20th century comfort, versatility and practicality.

Recognizing this desire, a number of furniture manufacturers are making furniture that combines the best of both worlds.

People are trading in their waterbeds and futons for four-posters, sleigh beds and beds with novel headboards. Chaises blend traditional formal style with ultimate 20th-century comfort. Traditional upholstery is deeply cushioned.

And, with smaller living spaces, people are filling their multipurpose rooms with multipurpose furniture. Sofas become sleepers, antique reproduction cabinets house computers, chests camouflage a TV and VCR.

No matter what your tastes are, chances are you need to brush up on furniture facts so you'll be able to identify a Chippendale chair from a Duncan Phyfe, or a Louis XV chair from a Queen Anne.

Sheffield School of Interior Design can help. The school has recently revised and published two books - "Mediterranean & French Furniture" (24 pages) and "Early American Furniture" (16 pages). Each of these books, complete with sketches to illustrate every style, costs $2 for postage and handling. They are available by writing to Sheffield School of Interior Design, 211 E. 43rd St., NY, NY 10017.