Glassjaw is a four piece (formerly five piece) band from Long Island, New York that was started in 1993 by vocalist Daryl Palumbo and guitarist Justin Beck. Since their inception into the Long Island music scene, they have been categorized as many genres; predominantly "Post Hardcore" but also "Hardcore Punk", "Experimental Rock", "Alternative Metal", "Progressive Rock", and "Art Rock". They have also gone under numerous line up changes, and over the years they have been influential in the progression of underground music scenes, spearheading the new Post Hardcore movement in the northeast with Thursday, and their music has since spread to the rest of the United States, Europe, and South America.