Hair is dead matter—something to shampoo, shape and sigh over when it falls wrong (or falls out). However, it is also a powerfully important matter; a site of self-expression and a repository of cultural identity. Throughout history, hair has been used as shorthand to signal power and social affiliation. It continues to play crucial—and contested—roles in religion, industry, the arts and politics. This summer, we’re untangling the many meanings of hair.