The ballad of John Barleycorn has hundreds (one count put it at 140 - 200 -- I'm only describing two (both of which are in the public domain)) of versions that are found going back to at least 1465 (from the James Ist Pepoysian collection as indicated by H Gorson (1607-1641). It is assumed that the story of John Barleycorn goes back even futrther. The most common poetic is that of Robert Burns (1759-1824).

There are questions about the origins of this poem. The Pengin Book of English Folk Songs says this about it:

This ballad is rather a mystery. Is it an unusually coherent folklore survival of the ancient myth of the slain and the resurrected Corn-God, or is it the creation of an antiquarian revivalist, which has passed into popular currency and become 'folklorised'? It is in any case an old song, of which an elaborate form was printed in the reign of James I. It was widespread over the English and Scottish countryside, and Robert Burns rewrote a well-known version..

John Barleycorn refers not to a person but rather a god representing the field that is to be harvested, and in paticular barleycorn itself from which beer and mead are brewed.

The sung version (below) has been covered by Jethro Tull, Trafic, Steeleye Span, Steve Winwood, The Watersons, (and many other celtic folk groups) and has been sung at countless Renaissance festivals and SCA events.

Adam, Cain and Abel staggered
manfully across the field carrying a
plough, a harrow and a grain of
wheat... John Barleycorn--
mysterious intimations from above
told them to dig three deep furrows and
bury him -- this done they returned
home and started to draw up plans for
the first ale house.
This verse is not found in all versions, and may put names to the three men that are later mentioned. This puts this as ancesteral time and much along the lines of "once upon a time" or more aptly, "in the beginning". This verse is spoken and not sung, singing begins at the second verse.
There was three men come out of the West
Their fortunes for to try
And these three men made a solemn vow
John Barleycorn must die.
They ploughed, they sowed, they harrowed him in
Throwing clods all on his head
And these three men made a solemn vow
John Barleycorn was Dead.
The sun sets in the west and thus is the portion of the compass that represents death (the sun rises in the east and thus east is birth). The thing to realize here is that the 'birth' happens in the fall months and thus the men from the west who 'kill' John Barleycorn are also responsible for his birth. It is possible that these three men also represent the three months of the year of the fall - the season that kills the plants. An alternate version the first half for this verse is:
There were three men
Came from the west
Their fortunes for to tell,
And the life of John Barleycorn as well.
The verse tells of people planting the grain in the ground and covering it with dirt.
They let him lie for a very long time
Till the rain from heaven did fall
Then little Sir John he raised up his head
And he soon amazed them all
They let him lie till the long midsummer
Till he looked both pale and wan
Then little Sir John growed a long long beard
And so become a man
Here we have the spring and summer where at first the grain pops out of the ground after it rains - which amazes people. After midsummer the corn grows a beard which is actually refering to the tassels on grain. And so the grain matures.
They hired men with the scythes so sharp
To cut him off down by the knee
They rolled him and tied him round by the waist
Served him most barbarously
They hired men with the sharp pitchforks
Who pierced him to the heart
But the loader served he served him far worse than that
For he bound him to the cart
And so it is harvest time where people with sharp scythes cut down the corn and then time it up. After being tied up the bales are tossed into a cart with a pitchfork.
They rode him round and around the field
Till they came into a barn
And there they made a solemn mow
Of poor John Barleycorn
They hired men with the crabtree sticks
Who cut him skin from bone
But the miller he has served him far worse than that
For he ground him between two stones
And the harvest continues where they took the corn to the barn and threshed it with crabtree sticks. In corn, rather than cutting skin from bone this removes the seeds from the rest of the plant. At which point the miller would take the corn and then ground it between two stones to make flour.
They've wheeled him here, they've wheeled him there,
They've wheeled him to a barn,
And they have served him worse than that,
They've bunged him in a vat.
They have worked their will on John Barleycorn
But he lived to tell the tale,
For they pour him out of an old brown jug
And they call him home brewed ale.
At this point, we see the cycle of rebirth for John lived to tell the tale.
Here's little Sir John in the nutbrown bowl
And brandy in a glass
And little Sir John in the nutbrown bowl
Proved the stronger man at last
For the hunter he can't hunt the fox
Nor so loudly blow his horn
And the tinker he can't mend his kettles or his pots
Without a little bit of John Barleycorn
And so after distilled you have some "Sir John in the nutbrown bowl" and brandy in the glass (from the wine). The very last part of this verse shows the parts of life that drink some - the hunter and the tinker.

There is some older pagen implications in this ballad too that describe the ritual breaking down of a person and building them up into a new (spiritual?) being. Furthermore, the four elements show up here with scythes being swords or daggers representing air (the suit of swords in Tarot is linked to the air). The crab-tree sticks are staves or wands and represent fire. The stones of the miller clearly refer to earth and the old brown jug is a cup which represents water. Some go further and link the vat to a cauldron and the womb.

In some traditions, a scarecrow like effegy was made and carried from field to field and then burnt which would release the spirit of John Barleycorn back into the field so that it may be reborn again the next spring.

The Robert Burns version is firmly written in quatrains of the form ABCB with a strict meter. It tells very much of the same form:

There was three kings into the east,
Three kings both great and high,
And they hae sworn a solemn oath
John Barleycorn should die.

They took a plough and plough'd him down,
Put clods upon his head,
And they hae sworn a solemn oath
John Barleycorn was dead.

But the cheerful Spring came kindly on,
And show'rs began to fall;
John Barleycorn got up again,
And sore surpris'd them all.

The sultry suns of Summer came,
And he grew thick and strong;
His head weel arm'd wi' pointed spears,
That no one should him wrong.
The first two verses here are very much along the same lines as the first verse of the first version, though here three kings are mentioned rather than three men. In addition the kings here come out of the east which refers to the direction of birth. Furthermore, the description of the grain in the summer being described with long pointed spears and thick and strong.
The sober Autumn enter'd mild,
When he grew wan and pale;
His bending joints and drooping head
Show'd he began to fail.

His colour sicken'd more and more,
He faded into age;
And then his enemies began
To show their deadly rage.

They've taen a weapon, long and sharp,
And cut him by the knee;
Then tied him fast upon a cart,
Like a rogue for forgerie.

They laid him down upon his back,
And cudgell'd him full sore;
They hung him up before the storm,
And turned him o'er and o'er.

They filled up a darksome pit
With water to the brim;
They heaved in John Barleycorn,
There let him sink or swim.

They laid him out upon the floor,
To work him farther woe;
And still, as signs of life appear'd,
They toss'd him to and fro'

They wasted, o'er a scorching flame,
The marrow of his bones;
But a miller us'd him worst of all,
For he crush'd him between two stones.

And they hae taen his very heart's blood,
And drank it round and round;
And still the more and more they drank,
Their joy did more abound.
At this point we have the refrence to the spirit of John Barleycorn and his life blood - that of beer. And as a person drinks, the more joy that does go around
John Barleycorn was a hero bold,
Of noble enterprise;
For if you do but taste his blood,
'Twill make your courage rise.

'Twill make a man forget his woe;
'Twill heighten all his joy;
'Twill make the widow's heart to sing,
Tho' the tear were in her eye.

Then let us toast John Barleycorn,
Each man a glass in hand;
And may his great posterity
Ne'er fail in old Scotland!
And drinking will make your courage rise, it will make a person forget his problems and make the joy all that more. Furthermore it reduces the inhibitions of a person - making the widow both sing and cry. So, let us toast to John Barleycorn with a glass in hand.