A comprehensive book about what is a bird that should fascinate general readers who want to know more about them, yet still contains information that would interest the more scientific minded. It also includes lots of wonderful images and illustrations of birds that should keep those keen on seeing birds interested.

Chapter one gives an overall view of birds, from their evolution from dinosaurs to their variety, biology, anatomy and lifestyle.

Chapter two looks at the skin, scale and, especially, the feathers of birds. The various kinds of feathers are described along with their various functions like providing thrust, lift or insulation. Feather structures are shown and the various ways feather colours are produced (via pigments or from their structure). Also described are the different ways birds moult and maintain their feathers.

Chapter three looks at the muscles, skeleton and nervous system of birds and shows how they are similar or different from that of mammals and other groups of animals. Bird skeletons are hollow, but still strong, with a very flexible neck and interesting skull. The muscles are organized differently for flight. Their feet, too, differ based on their lifestyle. Birds' brains are organized differently from humans too, and can change depending on the season (for breeding or migrating, for example). Their sensory organs include a sensitive bill and eyes that perceive the world differently from us.

Chapter four looks as the physiology of birds, it how they live and reproduce in different environments. Getting water and staying at the proper temperature are a challenge for birds, both large and small. Their respiratory system is more efficient compared to mammals. Birds also separately evolved a four chambered heart. Birds also evolved ways to maintain their temperature under different conditions. Their digestive system is simpler than mammals, but birds have the ability to change the size of their organs in demand, for example during migrations. This also extends to their reproductive organs, which can become active under the proper environmental and other conditions.

Chapter five looks at how birds get around, primary by flying or running (non-flying birds). A look at how the shape of wings (and tails) determines how efficient birds are at takeoff, flying, manoeuvring, gliding, and so on, is shown. Looking at the metabolism of birds, shows how they are able to sustain flight for longs periods of time (by using fat for fuel and an efficient antioxidant system to repair metabolic damage). The various flying styles are also shown, including the ability of birds to sleep and fly with only one side of the brain active. The ability of running, swimming and diving birds are also covered.

Chapter six looks at how birds navigate and migrate. Birds migrate all over the world as the seasons change. Through experiments and small tracking devices, more is now being learned about how and when birds migrate, which helps with conservation of habitats along migration routes. How birds migrate and navigate is still being studied, but birds are known to use built in magnetic compass, memory and navigational clues during migrations. The bodies of birds also change during migrations. But migrations are risky, with artificial lighting, glass buildings, stormy weather and, now, climate change affecting migratory patterns.

Chapter seven looks at how birds East and footage for food. Birds eat lots of things, from meat to plants and carrion. Some are generalist feeders, while others are specialist. Diets of birds can vary with the seasons or when breeding (to make eggs and feed their chicks). The behaviour of birds us also affected by how they gather their food: from predators to carrion eaters, fishes, fruits, insects, underground or shore creatures and even blood. Birds can sense for their food using their breaks or their sense of smell. Some birds have mastered the use of tools to find food, while others hoard it.

Chapter eight looks at how birds communicate and socialize. Most birds practice monogamy for breeding, but genetics studies have shown that while birds may be socially monogamous, genetically they may not. Other birds practice various form of polygamy. There are also many ways birds attract mates, from songs and bright colouration, to dance and building architecture. Mating choice also depends on how genetics affects the performance of birds. Birds may be solitary or group together, possibly with other birds, giving rise to a social hierarchy that is still being studied. These groups may also be a way to spread information, like ways to get food, in interesting ways. Finally, birds can form mutualism with other animals for common benefit. Social living is not without problems, like the spreading of diseases.

Chapter nine looks at how birds reproduce, through eggs. The various ways birds breed are described, as well as how climate change can affect their breeding success. Males usually compete for mates in various ways like getting territories, singing, visual displays and so on. Nests are built to hold eggs and range from simple one to elaborate houses. Birds may also build individual nests or nest in huge colonies. Eggs may also differ in size, colouration and shape, although we aren't certain why they differ. When eggs hatch, chicks may either be born masked or feathered, affecting how they are taken care of. Some birds, of course, are parasites and lay eggs in the nest of other birds.

Chapter ten looks at the relationship between birds and humans. Birds have been used as symbols since ancient times, from religion to fashion, arts and technology. Birds have been domesticated for food, and kept as hunters and pets. This close relationship also creates problems, like birds diseases that spread to humans (bird flu), being hunted to extinction, or threatened via climate change and pollution, or the pet trade. But agreements and conservation may yet help to save birds.