Interface design encompasses three distinct, but related constructs: usability, visualization, and functionality (Vertelney, Arent, & Lieberman, 1990). Recently, a fourth component of interface design has emerged as a critical factor: accessibility. Interface design is most often associated with the development of Web pages, computer software, and multimedia, but is relevant to the creation of any instructional media or technical equipment. User Interface Design increases the intuitiveness, efficiency, and comfort level with a product, which translates into product acceptance and use. You need both good technology and usability for a successful product launch.- A. Wheeler