The Second Viennese School (German: Zweite Wiener Schule, Neue Wiener Schule) was the group of composers that comprised Arnold Schoenberg and his pupils, particularly Alban Berg and Anton Webern, and close associates in early 20th-century Vienna. Their music was initially characterized by late-Romantic expanded tonality and later, a totally chromatic expressionism without a firm tonal centre, often referred to as atonality; and later still, Schoenberg's serial twelve-tone technique. Adorno said that the twelve-tone method, when it had evolved into maturity, was a "veritable message in a bottle", addressed to an unknown and uncertain future.[1] Though this common development took place, it neither followed a common time-line nor a cooperative path. Likewise, it was not a direct result of Schoenberg's teaching—which, as his various published textbooks demonstrate, was highly traditional and conservative. Schoenberg's textbooks also reveal that the Second Viennese School spawned not from the development of his serial method, but rather from the influence of his creative example.