It takes a whole universe to make one small black bird. Swifts are among the most extraordinary of all birds. Their migrations span continents and their twelve-week stopover, when they pause to breed in European rooftops, is the very definition of summer. They may nest in our homes but much about their lives passes over our heads. No birds are more wreathed in mystery. Captivated by swifts throughout his fifty years as a naturalist, Mark Cocker sets out to capture their essence. Over the course of one day in midsummer he devotes himself to his beloved black birds as they spiral overhead. Yet this is also a book about so much more. Swifts are a prism through which Cocker explores the profound interconnections of the whole biosphere.