Musicians write notes down on a staff: five lines with four spaces between them. You don't need to read music to play, but knowing the basics helps a lot, and it isn't hard. Click any note on this page to hear it.
Every line and every space is one letter of the musical alphabet. Going up from a line to the space above it is the next letter. Here are the from C up to the next C, walking up the staff (in this order they're called the C major scale; more on that in the Scales chapter):
Notice that a step on the staff is always the next letter, whether that's a whole step or a half step (E to F, B to C). The staff shows letters; the W and H steps are hidden in it.
The sign at the start is the clef. It tells you which letter sits on which line. The treble clef (or G clef) curls around the second line from the bottom, which makes that line a G. From there you can count to any note. The lines are E G B D F, often remembered as "Every Good Boy Does Fine":
The spaces spell a word, F A C E: "FACE".
Notes above or below the staff get short extra lines, called ledger lines, that continue the staff just for that note. The C one ledger line below the treble staff is middle C (C4), the C in the middle of the piano.
Low notes would need many ledger lines, so they get their own clef. The bass clef (or F clef) puts F on the second line from the top, between its two dots. Its lines are G B D F A ("Good Boys Do Fine Always") and its spaces A C E G ("All Cows Eat Grass"):
Here is the C major scale an octave lower, on the bass staff:
Middle C sits right between the two staves (the plural of staff): one ledger line above the bass staff, one below the treble staff. Piano music uses both staves together, the right hand on the treble, the left on the bass.
A or is written just before the note, on the same line or space. It counts for the rest of the bar, too (a bar is a short section of music between two vertical bar lines; more on the next page).
Many songs use the same sharps or flats all the way through (they belong to the song's key: its home note and the scale it uses, explained in the Keys chapter). Instead of writing them every time, they're written once at the start of every row of music, as the key signature. For example, the G major scale has one sharp, F♯. Written out it looks like this:
With the key signature, every F is played as F♯, without a sign on the note:
The circle of fifths tells you which sharps or flats each key has.
Guitar music is written on the treble staff, but it sounds an octave lower than written, so that it fits on the staff without lots of ledger lines.
Many guitarists read tab instead. Tab has six lines, one per string, with the high e string on top, just like the fretboard on this site. A number tells you which fret to play on that string, 0 means the open string. Here is the C major scale again, with its tab:
The staff tells you which note to play and how long; tab tells you where to play it, but usually not for how long. That's why many songbooks show both. For chords, guitarists use chord diagrams.
Next: Rhythm Basics