This document provides an overview of interval ear training. It defines an interval as the distance between two notes and explains that learning intervals is important for developing relative pitch. This allows musicians to play by ear, improvise, and write music easily. The document outlines different interval types, recommends starting with seconds, thirds, fourths, and fifths, and provides tips on learning intervals through reference songs, solfege, or pure recognition drills. It also explains how intervals can help with chord and melody recognition as well as improvisation and playing by ear.