Aristotle prized friendship. Kierkegaard judged it sinful. But from playground to grave, friendships play a critical role in our lives. Friendships define and even replace relationships with siblings and parents; they can last decades longer than some marriages, and be just as turbulent and passionate. With 'the big society' and social networking dominating the headlines, modern friendships and how we create and maintain them are very much under debate.

In The Book of Friendship, Josie Barnard explores this elusive and potent phenomenon. Moving seamlessly from Boudicca to Jennifer Aniston, from Nietszche to Morecambe & Wise, she examines how friendship is affected by class, gender and geography, and the circumstances that can turn a passing acquaintance into a lifelong friend. The Book of Friendship discusses with wit, intelligence and sparkling insight every aspect of this alluring, uplifting, vital relationship.