Why Do We Sleep?

Everything you ever wanted to know about sleep but were too exhausted to ask.> ¿    What are circadian rhythms and how do they affect our energy levels throughout the day? ¿    What are dreams for and how do they happen? ¿    What are the different stages of sleep? ¿    Do animals experience sleep the same way we do? With clear texts and bright, distinctive illustrations, this is a great introduction to a subject that has fascinated us since ancient times, and an engaging tie-in to biology and natural sciences curriculums.