I wonder why the sea is salty

The perfect introduction to the oceans, featuring mountains under the sea, singing whales, deep-sea divers and much more. This highly popular and long-running series has been revamped for a new generation of readers, with a clean, crisp redesign and colourful covers. The series explores questions that young readers ask about the world around them in an unrivalled child-friendly style. The conversational format is perfect for delivering solid information in a natural, amusing and imaginative way.