Back in the 17th and 18th centuries, almost every well-dressed gentleman wore a snug-fitting garment under his top coat for extra warmth.

According to fashion historians, this garment was sometimes called a "waistcoat" or "vesture" (a now obsolete word meaning covering or wrapper). It was the ancestor of the modern vest.Today's version is much sleeker and shorter. And, obviously, the name has been abbreviated, too. What's more, vests no longer are confined to the male domain. Now, women are wearing them as well in dozens of fun and fashionable incarnations.

This summer, fun and fashionable vests are really hot. According to merchants around town, ladies of all ages are buying the smart little accessories to wear now or tuck away until the first cool, crisp days of fall.

When the days turn cool, vests will be appearing in rich velvets, supple suedes, luxurious leathers and colorful corduroys. But for women who can't wait until then to wear the style, lightweight and airy materials - silk, rayon, cotton and linen - are the best choices.

The main thing at this time of year is to keep cool and comfortable. And it's possible to accomplish this goal and still look stylish, stresses Lanny Bernard of the Chalk Garden.

"A lot of women tell me they hate hot weather because it's so hard to wear blazers," she says. "That's where vests come in. A vest can tie everything together just like a jacket - and in the right fabrication, it isn't nearly as warm."

Another great thing about vests, she continues, they'll go with almost any outfit - whether the ensemble is for loafing around on Saturday morning or stepping out on Saturday night.

From basic to beautiful, from sporty to spectacular, you can find a style suitable for almost every occasion. Patchwork versions are especially popular here in Salt Lake City. Other hits of the season: tapestries and brocades; vests with antique buttons; vests that are attached to blouses; and styles featuring quilted effects, floral patterns, animal motifs and elaborate embroidery.

Speaking of elaborate embroidery, Bernard has several vests in stock that are the handiwork of a talented local designer, Mary Coldesina. They feature a variety of motifs - many Oriental in tone - and are so intricate and colorful that they could easily hang on a wall as works of art. They're fashion collectibles.

Collecting vests - whether they're one-of-a-kind originals or mass-produced items that make no pretenses at being art - is a smart move. Almost everybody who's in fashion will tell you it pays to invest in a vest. And the reason is simple. The style, because it is so classic, has tremendous staying power. It can be worn year after year in many different ways and never look dated.

Some ideas:

- A sporty number - maybe one in plaid cotton - can be worn over a T-shirt and combined with jeans or shorts.

- A dressier version - maybe a floral print - can be teamed with a linen blouse and tailored skirt.

- An elaborate style - one trimmed with beads or lace - can turn a simple cotton skirt and voile blouse into a spectacular evening outfit.

- A sweater vest - try a cool cotton knit - can give a lift to an ordinary shirtdress and protect you against office air conditioning.

The list of possibilities is virtually endless!