How do you know which way to go if you do not know where you are? And how can you plan for the future if you do not know the state of the present? If we are concerned about the environmental future of Britain and Ireland, then we must know as much as possible about its present condition.

Happily, this country has never been short of expert naturalists – people who have a particular affection for bumblebees and bats, who take pleasure in noting the dates of the changes that take place each year in the woodlands and hedgerows, on mountainsides and heathlands, who chart the arrival of returning migrants in spring or the arrival of first-time immigrants. This book contains the reports of over 40 of the most dedicated of such experts, professional scientists who devote their lives to studying their chosen subjects.

Their accounts, needless to say, report change. That is hardly surprising. The natural world, everywhere, is changing and has always done so. It changed when human beings settled these islands in the wake of the retreating glaciers 13,000 years ago. They were themselves the instruments of change. Over the centuries, they cleared forests, cultivated the earth and introduced new species of animals and plants. They even modified existing species and turned them into something quite new.