This article originally appeared on Medium.

This series on listening to jazz opened with an introduction to some of the greatest jazz musicians and works of the last 60 years. Many people listen to jazz and feel torn — there’s something they like about it, but they’re also a bit confused. Some parts seem to repeat, some don’t repeat at all. In the same song, you might have parts that are very structured followed by parts that seem chaotic and random. It’s hard to enjoy the music if you feel confused by it.

So let’s clear up some of the confusion.

First, what is jazz? There’s no one answer to that, but the overwhelming majority of jazz played in modern times starts with an organized song. That is, a tune with a fixed number of measures, a repeating rhythm, a melody, and a harmony. At some point, one or more of the musicians will begin to improvise, to spontaneously play new notes and even chords. After awhile, the band will likely go back to playing the recognizable tune that the song started on.

Often, the tune is organized into sections, which is true of many popular music forms. In fact, most jazz fits one of these two models:

A blues. Like jazz, there’s no one definition of the blues, but there are some things that most blues share when it comes to the musical aspect. Most have only one section, made of three lines, each four measures of four beats long. The lyrics fit this pattern, too. Here, for example, are the lyrics to Robert Johnson’s famous Crossroads:

I went down to the crossroads, tried to beg a ride
I went down to the crossroads, tried to beg a ride
Nobody seemed to know me, everyone just passed me by

This is a classic blues because the first line makes a statement. The second line is very similar except that its sung higher, so it sounds like a response. The third line starts higher still, but takes us down and back to the first line. You could say the third line is a response to the first two. So this pattern of call and response in both the lyrics, melody and harmony permeates the blues.

Many jazz songs are blues. Charlie Parker is a great example of a jazz musician who elaborated on the blues. Famous Parker tunes like Au Privave, Blues for Alice, and Billie’s Bounce are blues tunes that Parker has “jazzed up.” Parker’s playing career overlapped, for example, with blues greats Muddy Waters and Howlin’ Wolf. What’s the difference between their versions of the blues? Largely, that Parker has taken the basic chords (the harmony) of the kind of blues Waters and Wolf played and added many more chords that provide a more fluid and dynamic background to the tune. Parker was one of the great geniuses of expanding the blues that ever played.

Standard tunes. The word standard in this context has two means. Mostly, it means the assemblage of popular tunes taken from shows and movies that were standard fare for singers and bands in the 1930s and ’40s. It has an additional sense of being written in a standard way.

That standard way is often referred to AABA. What that means is that the first verse of the song (the A section) repeats twice. This A section is generally going to be between 8 measures and 24, with 12 or 16 the most common. Then there will be a new section — called the bridge — which has a different melody, harmony and often mood. Then the A section will repeat, and we’ve finished one cycle of the song, one full chorus.

If you listened to The Bridge by Sonny Rollins on our list of great jazz by great artists, you heard God Bless the Child, written by Billie Holliday. You might have heard Blood, Sweat and Tears do this as well back in the 1960s. In any vocal version, you will find these lyrics:

Them that’s got shall have
Them that’s not shall lose
So the Bible says and it still is news
Mama may have, Papa may have
But God bless the child that’s got his own, that’s got his own

Yes the strong get smart
While the weak ones fade
Empty pockets don’t ever make the grade
Mama may have, Papa may have
But God bless the child that’s got his own, that’s got his own

Money, you’ve got lots of friends
They’re crowding around your door
But when you’re gone and spending ends
They don’t come no more

Rich relations give crusts of bread and such
You can help yourself, but don’t take too much
Mama may have, Papa may have
But God bless the child that’s got his own, that’s got his own

The first two stanzas are A sections. The B section begins with Money. Musically, it’s different than the prior two stanzas — the A sections start with major chords, the B with minor chords, and are otherwise different.

The part of the song that begins Them that’s got shall have, them that’s not shall lose is the A section.

In modern popular music, the Beatles are a great example of a band that often had bridges in their songs. For example, in the song Michelle, when Paul sings “I need you, I need you, I need you,” that’s the bridge.

Like most things musical, there are many variants to the AABA form, but most of them are just variations between the A sections.

The most notable exception to the above is free jazz, in which to one degree or another there is no fixed melody, harmony, rhythm or number of measures. Players just react to each other. In practice, much free jazz has a structure, it’s just minimal. Perhaps the bass player lays down a groove, and everyone goes from there. Then at some point, one of the players plays something noticeably out of that groove, and the band follows. But free jazz actually makes up a small portion of jazz. Many people mistake structured jazz that has very long solo, improvisational sections for free jazz. Both Coltrane’s A Love Supreme and Mingus’s The Black Saint and the Sinner Lady are examples of this. In truth, the soloist is playing over structured rhythms and chords played by the rest of the band. The sections may not repeat as much, and the whole composition is more like a classical one where themes appear and reappear. The difference is that the thematic development in jazz happens through both composed sections and improvised sections.

That brings us to the next thing to listen for — how does the band work?

Let’s start with smaller jazz bands that have six of fewer members. The band is typically divided into a front line and a back line. The back line is referred to as the rhythm section — minimally bass and drums, but possibly a chordal instrument like piano, guitar, vibes or organ. The rhythm section provides a steady beat and between the bass and any chordal instruments (instruments that can play more than one note at a time), lays down the basic harmony.

The front line — typically saxophones or trumpet — will usually play the melody over the rhythm section.

As the tune begins, the band will play the tune with the arrangement described above. In jazz the tune is often described as “the head.” These are the notes written on sheet music, if that exists. The band will often play the tune twice through.

After that, the rhythm section will continue playing something similar to what they played behind the head. In turn, one or more of the front line players, and potentially some of the rhythm players, will solo while the rhythm section plays.

In jazz, solos are improvised — the player makes them up as he or she goes along. That’s very different than in classical music, where the composer has written the solo as part of the composition.

So how can a player make something up while they are playing that still sounds like it belongs to the song? They use the harmony that the rhythm section is playing as a starting point. As each chord transitions to the next, some notes may stay the same and some may change. The soloist can use either the steady note or the changing one as a stepping stone to create a new melody. The soloist can also add notes to the chords, or play notes that suggest a different, but equally valid, chord.

Try it yourself. Put any kind of song on you like and try and hum or sing an alternate melody to it. Just do that “doobee doobee do” thing. You may be surprised to find that you can occasionally improvise something that you think sounds cool. If you practiced and observed what works and doesn’t work, you’d get better at it.

And that’s how jazz musicians get better. Some tunes are very easy to improvise on, some are quite difficult. Some are easy to play something that doesn’t sound terrible, but hard to play something that sounds like music and has a real feel to it. You probably know people who can speak very well but don’t seem to say much. The same is true in jazz! But it’s also true that over years many players hone their skills and can just find amazing new melodies, harmonies and rhythms hiding in familiar tunes.

I’d be remiss not to note that with some jazz tunes, the improvisation takes place over a different set of chords than the melody. This is usually because the chords to the melody don’t lend themselves that well to improvising. A good example of this is the tune Stolen Moments by Oliver Nelson, featured on the album The Blues and the Abstract Truth (great title!). It has a cool head but the solos are just over a blues in the same key as the head.

Improvisation is the single most important creative act that makes jazz what it is. As you listen to a tune, notice how each succeeding soloist is different. Some may add a lot of flavor to the tune by adding key notes into the harmony that make it sound edgier or more diffuse or sadder or happier. Others may change the rhythmic feel entirely — a ballad can become a march, a swinging dance tune can become a Latin dance tune. The soloist is free to try a lot of things, but also needs the rhythm section to not get in the way, at the minimum, or to bring out the soloists interpretation in the best case.

This is where jazz solos tend to differ from rock or blues solo. For example, Eric Clapton probably became broadly famous first for playing a long fiery solo on the same Crossroads we discussed earlier on the Cream album Wheels of Fire. It’s a really great blues/rock solo, but he does nothing to develop the melody, harmony or rhythm. Great jazz solos tend to be more exploratory, although it can be hard as listener to described how the tune is changing. You just feel that the soloist has gone somewhere new.

Let’s go back to Kind of Blue as an example. The first song, So What, starts with some interplay between bassist Paul Chambers and pianist Bill Evans for the first 34 seconds. They probably made that up on the spot. At 35 seconds, the two begin the theme that is the melody of the song. At 50 seconds, the horns join in as a kind of chorus, adding to the chordal notes that Evans is playing.

This goes on as they play through the tune once. At 1:28, Miles begins his solo. The bass is no longer playing the melody, but playing what’s called a walking bass — four notes per measure that outline the chords. Evans continues to play the chords in the background. They’re very simple chords, so he focuses more on rhythmic stabs that contrast with Chambers’ steady bass. Miles’ solo is very controlled — he plays a limited set of notes that, for me, give a soulful tinge to the driving bass line. If Miles’ solo was a painting, it might be a Cezanne — angular and spare, yet striving for a fuller dimensionality by stripping away the extraneous.

At 3:22, Coltrane starts his solo. It starts out not that different than Miles does, but within 15 seconds has developed a very different feel. Evans changes the way he plays chords behind it. Coltrane continues to develop his solo, pausing occasionally for contrast. He plays many more notes than Davis, but his solo also has a very different feel — tenser, more searching. Evans’ chords complement that. Whereas Miles is playing Japanese brush strokes that hint at a more complex framework, Coltrane is playing Jackson Pollack — he’s laying down string after string of notes that comprise dissident chords not being played by the rhythm section. At the same time, the rhythm section maintains their steady presence. The contrast between the two drives this section.

At 5:13, Adderley comes in with his solo. His is quite different than either of the two. It has more of a bluesy, swinging feeling. It’s also very masterfully constructed of a set of phrases that lead to each other. For me, this section has an almost R&B or gospel feel to it. It sounds almost written out, yet that’s highly unlikely. He doesn’t evoke a painter for me because he feels direct — like he’s just talking to me. Adderley (and Coltrane) had most likely never played this tune before, or if he had, as kind of a fragment.

At 7:02, it’s Evans’ turn. Because there’s no longer a chordal instrument, the three horns play some notes in unison behind him, forming chords. It’s just like singers in a chorus singing the do-me-so of a chord. Evans is the first chordal solo, and he makes the most of Miles’ tune to give an impressionistic rendering. For me, he’s Mark Rothko.

Evans only takes one chorus and hands it over to Paul Chambers at 8:15. Chambers plays the head again. In jazz, this is known as the head out, as in taking the song out to the end.

All four soloists play very different notes to the same rhythm and harmony. Each brought different temperaments and discovered something different when they soloed, and for the horn players who took multiple choruses, each chorus built on the last. That’s the whole point. For you as the listener, it’s like being able to look at a great painting from the front, back, and side, in bright light, in dim light, and so on.

Miles’ bands played this tune live for at least five more years. As time went by, his bands played it faster and faster, until it was actually too fast for the bass to play the entire melody line. The whole feel of the tune changed and evolved over time. For many great jazz musicians, playing the same tune the same way for years goes against the grain. They want to push the envelope, find new sounds. If you hear a jazz record and then go see the artists live, don’t be surprised if they play your favorite tunes completely differently.

Both on record and live, you may find some jazz bands caught in a sort of round robin formality to the solos. The band plays the same behind each, as if they were in a different room. Some soloists are just showing off — they have a technique that will work with this tune and they want to show how fast, smooth, edgey, loud or whatever they can be. As a listener, you want to hang loose and give your brain a chance to absorb the music, but you don’t have to like it. You may, over time, want to get a better sense of why and what you do or don’t like. That may take some knowledge, though, and you may not want to or be able to technically analyze what you hear. So it’s OK to think “I liked that, even if I don’t know why” or the reverse. But in time, you’ll likely realize that you do or don’t like certain approaches: jumpy rhythms, jangly chords, long fluid melodies, or whatever. No worries — taste is valid.

For now, if this is all new to you, just let it happen. Feel the groove, feel how the tensions in the chords and the melody, how they resolve and evolve. Feel the energy of the music and how it makes you feel. That is, after all, the point.