Theory is an American fashion brand founded in 1997 by Andrew Rosen and Israeli-American designer Elie Tahari. In the early days of its establishment, Theory's target market was mainly office workers, a group of smart, active and fashionable professional women, and white-collar women who were looking for high-quality and classic designs, but also required to keep up with trends and wear innovative fabrics. Theory's design philosophy is "simple and elegant", and all garments are made of elastic fabrics to make guests more comfortable and show their sexy side.