Sinead Morrisey's 1996 debut volume, published when she was 24, marked her out as a poet to watch. Her exceptional fourth collection Through the Square Window, more than fulfils that early promise.
Avid for a world "clamouring to be experienced", her lyrics and narratives (she is equally good at both) teem with creatuers, ideas and people: Aristotle's theory of spontaneous generation, the gift of a dead hare, and Edwardian children caught on film. Lewis Carroll's Alice, appears several times.

As its title's nod to Play School suggests, the book dwells on childhood, with poems about an infant's acquisition of language, the rhymes and games of the nursery and the playground, and the transitoriness of childhood itself, likened to a passing royal visit. "Staring west/ at the last of a trail of dust", the parents stand at the kerb, memorising "the hair, the eyes,/ the inscrutable footmen. the marvellous horses."

In a couple of poems, the dead look in at the window and the book as a whole is poised between life and death. But Morrissey's writing is affectionate rather than sentimental, dark rather than morbid- a tribute to its vigour and formal deftness.

Shortlisted for the 2009 T S Eliot Prize and a strong contender for this year's Forward prize, Through the Square Window is an impressive addition to a fine body of work. It confirms Sinead Morrissey as the outstanding poet of her generation.