This document provides an overview of music theory concepts related to intervals. It defines major scales as having a consistent pattern of whole steps and half steps. It also lists the order of sharps and flats in a key signature. The document introduces melodic and harmonic intervals and how to count and name intervals based on the number of letter names between the lowest and highest notes. It describes the qualities of intervals within a major scale as either perfect or major and lists which specific intervals have each quality. It also states that if the upper note of an interval is part of the lower note's major scale, the interval will be perfect or major, but may be minor if the upper note is a chromatic semitone lower.