An aria in an opera - Handel's 'Ombra mai fu,' for example - gets along with an incredibly small number of words and ideas and a large amount of variation and repetition. That's the beauty of it. It's not taxing to the listener's intelligence because if you haven't heard it the first time round, it'll come around again.

The lullaby is the spell whereby the mother attempts to transform herself back from an ogre to a saint.

At somewhere around 10 syllables, the English poetic line is at its most relaxed and manageable.

A cabaret song has got to be written - for the middle voice, ideally - because you've got to hear the wit of the words. And a cabaret song gives the singer room to act, more even than an opera singer.

Free verse seemed democratic because it offered freedom of access to writers. And those who disdained free verse would always be open to accusations of elitism, mandarinism. Open form was like common ground on which all might graze their cattle - it was not to be closed in by usurping landlords.

"Love" is so short of perfect rhymes that convention allows half-rhymes like "move". The alternative is a plague of doves, or a kind of poem in which the poet addresses his adored both as "love" and as "guv" - a perfectly decent solution once, but only once, in a while.

A poem with grandly conceived and executed stanzas, such as one of Keats's odes, should be like an enfilade of rooms in a palace: one proceeds, with eager anticipation, from room to room.