I recently came across this book by American writer Christopher McDougall. It's a cracking read for any one with a casual or keen interest in running. Insightful, and gave a few explanations to questions about my own love/ hate relationship with running.
It's so good in fact I'm reading it again. A well told story, an epic adventure in search of a simple answer and backed up with loads of facts, with a fair bit of anthropology thrown in too.
Check it out! Even if you don't run its still an insightful read.