"A writer needs a strong passion to change things," asserts Roger Deakin in his "Notebooks", as he eloquently probes the poignant roots of his own fascination with trees. A sense of urgency pervades these evocative essays, stories and photographs; we must change our appreciation of the delicate environments in which we live, cease damaging and instead preserve and cultivate their beauty - which might first mean improving ourselves.

What exactly is nature and why do things function - and stop functioning - at all? One rainy day following her mother's death, Kathleen Jamie visits a pathology lab where she dissects a tumour- ridden colon while simultaneously examining the complex definition of nature. Jamie's sensuous writing thrives on powerful juxtapositions: our "intimate, inner natural world" and the outer; microscopic detail and philosophical pondering. (Jamie is one of only two female writers in the book.)

The contradictions and curiosities of human nature are set against physical nature. Paul Farley and Niall Griffiths detail their ambivalent relationship with the inner cities of their youths, as the desire to escape battles the impulse to return to the roots of who we are.

Why do some survive while others become extinct? Robert Macfarlane describes the "ghosts of nature" - a soft-shell sea turtle, the desert bighorn, the sawfish - those lacking skills exportable beyond their environment, unable to adapt. But mourning at the loss inherent in nature is balanced with awe and joy at the capacities of regeneration. The appearance of exceptionally rare, dazzlingly white egrets, surviving in a changed environment, is one of the many small but potent symbols of hope which flutter throughout the pages of this collection.