# Introduction to Post-Tonal Theory, Music theory

Atonality, twelve-tone technique, and pitch class sets

The 20th century broke tonality apart, and the Second Viennese School rebuilt music from first principles. This module introduces pitch class set theory, twelve-tone rows, and interval vectors through Berg's Lyric Suite and Webern's Five Movements for String Quartet.

Maestro · 5 lessons · approximately 102 minutes of material (not a mastery deadline).

## Before this module
- [Chromaticism & Late Romantic Harmony](/learn/theory/chromaticism), Wagner, extended tertian chords, and the edge of tonality

## What this module covers
1. **Introduction to Atonality**, Music without a tonal center, how to listen and analyze (14 min)
2. **Twelve-Tone Technique and Serialism**, Schoenberg's row, prime, inversion, retrograde, retrograde inversion (16 min)
3. **Pitch Class Sets and Interval Vectors**, The mathematical toolkit for atonal analysis (16 min)
4. **The Second Viennese School and Strings**, Berg's Lyric Suite and Webern's Five Movements analyzed (28 min)
5. **Post-Tonal Analysis Challenge**, Identify row forms, segment pitch class sets, analyze a passage (28 min)

## What comes next
- [Jazz Theory for Orchestral Musicians](/learn/theory/jazz), Extended chords, chord-scale theory, and the ii–V–I

## Where should I start with introduction to post-tonal theory?
The curriculum places Chromaticism & Late Romantic Harmony before this module. Review those topics if they are unfamiliar. The first lesson is “Introduction to Atonality”: Music without a tonal center, how to listen and analyze. The order is a study guide, not proof that every learner needs the same pace.

## How long is the introduction to post-tonal theory module?
The 5 listed lessons total approximately 102 minutes of material. That estimate describes lesson content, not the practice time needed to become comfortable with atonality, twelve-tone technique, and pitch class sets. Revisit one task at a time and use feedback from a teacher where physical technique is involved.

## What can I try here without an account?
The introduction to post-tonal theory description, lesson sequence and prerequisite links are public. There is no full worked lesson sample for this module yet. The linked public tools and references are free. A free account includes the complete five-lesson foundation module in each instrument and five lessons in music theory, with saved progress and no expiry. Later lessons require the relevant paid package.

## Continue in Arco
The complete five-lesson foundation module in each instrument and five music theory lessons are free with an account, including saved progress and no time limit. Later lessons require the relevant paid package. Public samples do not assess your physical technique or certify exam readiness.

[See packages and pricing](/pricing) · [Back to the music theory curriculum](/learn/theory)

Canonical source: https://arcosounds.com/learn/theory/post-tonal