The Persian reed-flute, or nay, is one of the simplest instruments in the world: a length of cane with a few finger-holes and a copper cap at the top where the flute-player directs his breath. But from this unprepossessing pipe come the subtlest melodies, sometimes blithe, more often achingly sad. Devotees claim that the nay is the closest of all instruments to the human voice; and indeed, its similarity to our own accents is almost spooky. On longer acquaintance, however, the nay has a chastened timbre that is foreign to us; it seems to be beseeching or lamenting in a language which we know but cannot translate. Were it not so breath-inflected, it would be tempting to imagine its voice as that of a mournful angel.

The great Persian poet Jalal al-Din al-Rumi (1207-73) introduces his vast Masnavi (the Persianised form of the Arabic math-navi meaning 'couplet') with the piercing soliloquy of a reed-flute. That sets the tone for what is to follow in the almost 26,000 verses of this astonishing poem - astonishing because for all its intense and often ecstatic spirituality, the Masnavi is also a colossal grab-bag of tales, apothegms, homilies, proverbs and bons mots, together with exquisite lyrical interludes. It ranges in tone from the rapt to the scabrous. Reynold A. Nicholson, who edited the text with prose ...