It's a bit weird to use a spoiler warning when reviewing a book that's over 800 years old. But 'The Conference of the Birds' ('Mantiq at-Ta'ir'), by twelfth century Sufi poet Farid ud-Din Attar, contains a philosophical twist that's best experienced firsthand in this 4500 line allegory.
In Persian mythology, the Simorgh (or Simurgh) is a giant bird, a benevolent deity as old as the world, related to the Greek phoenix and the Hindu Garuda. But its name in Persian also means '30 birds' ('si morgh'), a pun which Attar used for his story.
The story begins when the birds hold a conference lamenting the fact that they have no leader. The hoopoe then tells them about the Simorgh, the king of birds who lives behind the far-off mountains of Kaf.
It was in China, late one moonless night,
The Simorgh first appeared to human sight -
He let a feather float down through the air,
And rumours of its fame spread everywhere;
Led by the hoopoe, the birds set out to find the Simorgh. Like in the 'Arabian Nights', the central story provides a framework for countless smaller stories, parables and fables, in this case illustrating both the splendor of the Simorgh and the various moral shortcomings of the birds.
During their journey the birds pass seven valleys, each symbolic of a stage on their way to find God. Along the way, many birds give up, and when they finally find the Simorgh, only 30 birds are left. Here Attar makes use of the Simorgh word play in one vertiginous image of divinity:
There in the Simorgh's radiant face they saw
Themselves, the Simorgh of the world - with awe
They gazed, and dared at last to comprehend
They were the Simorgh and the journey's end.
They ask (but inwardly; they make no sound)
The meaning of these mysteries that confound
Their puzzled ignorance - how is it true
That 'we' is not distinguished here from 'you'?
The pilgrim birds have reached the ultimate goal of Sufism: the total union with God, which is to say the total realization of the fact that there is nothing but God, as God is the whole universe. (For a Western version of this pantheistic doctrine, see Spinoza.)
Then, as they listened to the Simorgh's words,
A trembling dissolution filled the birds -
The substance of their being was undone,
And they were lost like shade before the sun;
Neither the pilgrims nor their guide remained.
The Simorgh ceased to speak, and silence reigned.
In his essay 'The Simurgh and the Eagle', Jorge Luis Borges compared the Simurgh to the Eagle's head in Dante's 'Paradiso' (Canto XVIII), which is composed of thousands of just kings. (His verdict: "The Eagle is merely implausible; the Simurgh, impossible." Coming from Borges, I'd say calling an idea impossible is high praise.)
Summing up the genius of Attar's story, Borges writes:
The imaginative power of the legend of the Simurgh is apparent to all; less pronounced, but no less real, is its rigor and economy. The pilgrims go forth in search of an unknown goal; this goal, which will be revealed only at the end, must arouse wonder and not be or appear to be merely added on. The author finds his way out of this difficulty with classical elegance; adroitly, the searchers are what they seek.