"Cloud Book: How to Understand the Skies" by Richard Hamblyn is available from Amazon for £6.99 which is a 30% discount.
Amazon also have "The Invention of Clouds: How an Amateur Meteorologist Forged the Language of the Skies" by Richard Hamblyn for £5.99 - though it is a lot cheaper in their New and Used Section.
Click on the links below to go to the correct pages at Amazon where you can read more and buy the books if you want to.
Please note that all the information above is correct at the time of writing but that availability and price may change at Amazon.