If you're trying to learn how to play music, read music, or brush up on improvising and performing with other musicians, music theory is important. However, you don't need to know every last tidbit that the many theorists around the world have written down. You just need to become familiar with some of the basics.

Discussing form when talking about popular music is tricky because the term is often misused. Think of form as being the specific way a piece of music is constructed, with governing rules to that type of music’s construction. Genre, on the other hand, refers to a song’s style, such as the instrumentation used, overall tone of the music, and so on.

Simple time signatures are the easiest to count, because a one-two pulse in a piece of music feels the most natural to a listener and a performer. The following four requirements indicate that a time signature is a simple one: Each beat is divided into two equal components. If a single beat has more than one note, those notes are always grouped together to equal one beat.

Notes and rests in music are written on what musicians call a musical staff (or staves, if you’re talking about two). A staff is made of five parallel horizontal lines, containing four spaces between them, as shown. The two primary staves: the treble clef staff (left) and the bass clef staff (right).Notes and rests are written on the lines and spaces of the staff.

One of the most important things to remember about music theory is that music came first. Music existed for thousands of years before theory came along to explain what people were trying to accomplish when pounding on their drums.So, don’t ever think that you can’t be a good musician just because you’ve never taken a theory class.

The difficulty in putting together a Top Ten list of revolutionary music or musical movements is that so much of what modern Western civilization knows of revolutionary music is very limited. History is full of people like the Spanish priest Diego de Landa, who dedicated his life to destroying Mayan literature and history, or Emperor Jovian, who destroyed all non-Christian texts and musical scores in the Library of Antioch, or Genghis Khan, who famously sacked and destroyed the libraries of Iran and Iraq.

Understanding how to read the circle of fifths will help you understand the relation between music's major keys and their relative minor keys. A major key and its relative minor use the same key signature, which means they use the same sharps (indicated as #) and flats (shown as b) in their scales. When you read the circle of fifths, you'll notice that the major keys are on outside of the circle.

Minor scales are an important part of music theory. When you hear the term minor scales, you may be led to believe that this set of scales is much less important than the grand collection of major scales. Or you may think the minor scales are only for sad, sappy songs. But the truth is that the arrangements and tones (or note sounds) available in the minor scales — divided, according to composition, into the natural, harmonic, and melodic minor scales — can be much more flexible for a composer to use than the major scales alone.