A Hospital Odyssey, By Gwyneth Lewis

Only poetry could hope to handle fantasy of this order. Maris's husband has been diagnosed with cancer, and she is looking for him along hospital corridors which lead into an underworld - sometimes resembling the computer game World of Warcraft - peopled by figures from Greek myth and science fiction. A bad-tempered nurse, tapping away at files, transforms into a Great Spotted Woodpecker, a hissing spider is the mother of a dragon. There are realistic patients, who complain: "I've been buzzing the nurse... but nobody comes." In the last episode, Maris encounters a bewildered Aneurin Bevan, architect of the NHS.

What is most remarkable in a book of such exuberant invention is that the reader continues to believe in Maris's intense longing for her sick husband. But Maris is not only seeking her husband, she is doing battle for him against his illness. The ugly landscape of failing lifts and ill-lit basements becomes a metaphor for the inner space of the human body. On her way, Maris collects a strange band of helpers. These include Wilson, an affectionate talking greyhound, evidently a hero from the Wizard comic, Ludlow, a Knight Templar who was once a doctor, and Ichabo, an ambiguous figure from the Old Testament who comes to sacrifice his own eyes and organs in her service. As if in a courtly medieval romance, Maris has to choose between the doors of Peace, Love and Death.

Through the surreal events, Maris's emotions are everyday and convincing. She has to get back to her husband because he is having emergency treatment "and is all alone". Sturdily rejecting a druid surgeon who asks her, "What did he do wrong/To get the cancer?", she finds she can only put her trust in poetry and imagination. This sometimes bodies itself in puns: Lupus, for instance, a murderous auto-immune disease, is signalled when her loyal greyhound becomes a wolf.

For the most part, the texture of the poetry itself is clean and unfussy. Lewis uses a five-lined stanza, colloquial in tone and with flexibly placed rhymes. The word order is natural, and her lyricism is unforced: "I often leave my body's boat/To play in the bow wave. I use rhymes/ To catch stray dreams that happen to float/past me."

Somewhere at the opening of Book 9, Lewis begins to set up an airport, complete with terrorists and cancelled flights, and then halts herself to reflect that "RS Thomas/ told me once that I should choose/ between fancy and imagination". I was brought up short to ask myself: how much of this splendid fantasy is any more than fancy? The range of reference is so wide, we are intoxicated by it, from the possibilities of stem cell research to the myths of Eliade and the smear of her husband's bone marrow, "like a coastline on its glass slide". I came to feel that I trusted the myths rather than the mysticism which seemed too close to those New Age beliefs Lewis herself explicitly rejects. But you cannot argue with poetry. When she writes "We're filaments/ of light", I believed her, and so followed willingly after Ludlow as he softly blows over the mouthpiece of Hippocrates' wooden flute.

Elaine Feinstein's versions of the poetry of Marina Tsvetaeva, 'Bride of Ice', are published by Carcanet