MARC JACOBS

To say Marc Jacobs is influential is an understatement. He is a driving force whose designs set a distinct mood and define the top trends each season. Never a dull moment seems to be the designer's credo, as he turns out collection after collection replete with creative variety and sartorial wonder. One season he mines the '40s, the next he's taking us on a journey through a neon-painted '80s retrospective—keeping everyone from hip starlets to fashion editors in his grasp. Jacobs, who spends much of his time in Paris, launched his signature collection in 1986 and his secondary line, Marc by Marc Jacobs, in 2001. He also serves as creative director of Louis Vuitton.

REBECCA MINKOFF

In 2005, New York designer Rebecca Minkoff introduced her first handbag, the Morning After Bag, which quickly attained "it" status. After four years spent designing covetable accessories in her trademark leathers, studs, and edgy hardware, Minkoff launched her first ready-to-wear collection in 2009, riffing off a "downtown romantic" theme. The brand, which has become a favorite of celebrities like Eva Mendes, Kristen Stewart, and Jessica Alba, now encompasses accessories, footwear, apparel, handbags, and jewelry.

PRADA

Its name was lent to the novel and movie The Devil Wears Prada, and in real life the Prada design house, led by the extremely creative and intellectual Miuccia Prada, is always ahead of the fashion curve. An endless trendsetter, Prada (who in 1978 took over the reins of the family business, founded in 1913 by her grandfather Mario Prada as a leather goods shop) understands how to design modern clothing that has timeless appeal. The clean, feminine lines of the ready-to-wear collection, launched in 1989, have an ageless charm and are designed with a woman's curves and busy lifestyle in mind. Prada herself has called her designs a uniform for women.

DOLCE & GABBANA

Super-stylish and glamorous Italian fashion house Dolce & Gabbana, made up of Domenico Dolce and Stefano Gabbana, is known globally for its sexy, woman-friendly cuts. The design duo started their hugely popular label in Milan in 1985. Its luxe looks are popular with stars like Madonna, Emma Stone, Jennifer Lopez, Monica Bellucci, and Kirsten Dunst. In any collection, one might expect a bustier dress and formfitting pants and skirts. The Dolce & Gabbana empire also includes handbags, shoes, sunglasses, fragrance, lingerie, makeup, and eyewear
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