Denim is far more than just a cotton fabric. It has evolved and defined generations. Denim, and its sister-fabric, “jean,” have been with us since the Renaissance, but only in the 20th century did “denim” become the word for the cloth that “jeans” were made of.

Summer might mean a slowdown in retailing in some cities—but to the contrary in Manhattan! Native fashionistas swear that this is the best time of the year to “seek chic”—and why else do so many tourists come to visit? Now is the ideal time to replenish the casual part of your wardrobe, and there’s plenty to choose from. Every retail neighborhood in the city is on board, and denim is leading the charge, as more and more fashionable jeans boutiques move into Manhattan in 2008 and 2009.

Denim is far more than just a cotton fabric. It has evolved and defined generations. Denim, and its sister fabric, “jean,” have been with us since the Renaissance, but only in the 20th century did “denim” become the word for the cloth that “jeans” were made of. By the 1930s jeans had gained romantic appeal as the standard attire of the cowboy and the workingman, and by the 1950s they were standard casual wear nationwide. However, there’s no doubt that jeans were considered lower-class. People wearing jeans were sometimes refused service in restaurants and hotels, and even in the 1960s many public and private schools forbade their students to wear jeans. But jeans-wearers would not be denied, and by the early 1970s serious high-end fashion designers the world over started turning their attention to jeans. In the 1980s the “designer jean” craze was born and the rest is history. And that, very briefly, is why the humblest of garments has become a staple in everyone’s wardrobe—all the more so if you worship fine design and live by the pages of Vogue. The “beautiful people” of New York and elsewhere have long known that a $20,000 watch or a $50,000 necklace looks just as fabulous with jeans as with evening wear! Consequently, it’s the latest in designer denim that’s making the splash.

As you might expect, most of the big news in fashionable apparel is being made Downtown, in SoHo and near the Financial District.

The latest bombshell is the new 3,000-sq.-ft. flagship store that 7 For All Mankind is opening at 394 West Broadway (between Spring and Broome Streets). This retailer offers an extensive line of apparel and accessories for men and women, including some of the highest-end jeans available—so it’s appropriate that it should occupy one of the most prestigious buildings in such a fashionable neighborhood. A new G-Star boutique is coming to 441 Broadway by the end of the year: the Dutch urban apparel retailer’s third Manhattan location. The “raw” denim look is already setting a trend for daring men’s and women’s styles. French retailer, Comptoir des Cotonniers, known for its timeless sophistication, will début a first stateside store this September at 155 Spring Street. Hollister is planning to invade SoHo in the summer of 2009, with a mammoth flagship at 600 Broadway: a space that most observers had expected would house its parent retailer, Abercrombie & Fitch. (The two retailers sell similar product lines, but Hollister’s clientèle is typically a little younger and hipper.) This is perhaps in response to the success of Madewell, a division of J. Crew, which has established itself a few blocks down, at 486 Broadway. Marciano, a higher-end division of Guess, is slated to open a new store right between Hollister and Madewell, at 514 Broadway.

True Religion, another denim superstar, has launched its first Manhattan store on the Upper East Side, at 1122 Third Avenue (at 65th Street), followed by a second unit, at Time Warner Center near Columbus Circle. In July a third store will open, on Union Square at 863 Broadway. True Religion has also said it will open a store in the Financial District in October: 1,700 sq. ft. on two levels at 14 Wall Street. In the southern border of the Plaza District, the tri-level Diesel flagship store will open at 685 Fifth Avenue, just in time for Christmas. Here you’ll find nearly 20,000 sq. ft. of the cutting-edge denim fashion that sets the pace for the casual wear industry. Diesel will be rolling out a new luxury line there—Diesel Black Gold—as well as a new line of jeans that Diesel has developed in collaboration with Adidas.

Collaboration seems to be the trend within the jeans industry!

Alber Elbaz of Lanvin is currently working on a new denim line to be rolled out for Acne Jeans in 2009. Look for it to début at Acne Jeans’ first U.S. store, at 10 Greene Street, Downtown. Uptown, the big newsmaking partnership is about as unlikely a pairing as you could imagine: The oh-so-tony shirtmaker, Turnbull & Asser, is preparing a line of shirts for Jean Shop—plain white shirts that can be custom-dyed to the customer’s individual specifications—while Jean Shop has devised an exclusive line of jeans to be offered at Turnbull. You can observe the work of these strange bedfellows at Jean Shop’s flagship store in the Meatpacking District (435 West 14th Street), or at Turnbull’s Manhattan headquarters (42 East 57th Street).

Jeans are no longer an emblem of simplicity.

They have become a signature of functionality in fashion with many designers tailoring their lines to this need for comfort and style. So if you find yourself dying for denim in New York City, be of good cheer:

This is your year!