What are clouds? Just a collection of ice crystals or water droplets visible to everyone. Yet from time immemorial, they have been a source of endless fascination. Constantly moving and changing shape, clouds can often be calming and inspiring; at other times, when thunderheads or funnel clouds appear, they can be terrifying. In the sky are clouds and optical effects with names like sun dog, corona, silver lining, and glory. There's the green flash, sea smoke, the cap cloud, and sun pillars. And there are all those classifications we learned in school, but perhaps forgot; cumulus, stratus, nimbostratus, cirrus, and more. In 'The Book of Clouds', John Day, known around the world as 'The Cloudman' introduces, or reintroduces, us to earth's great skyscape. His spectacular portfolio of cloud photographs forms the centerpiece of these glorious pages. A stunning cloud chart, information on forecasting, observing and photographing clouds, and his 'Ten Reasons to Look Up' (the first one is, 'It's the greatest free show on earth'), show us how to use our 'inner eye' to really see the familiar fleeting forms that seem to float effortlessly above.