Who invented e-mail?

Over at the Times site, Errol Morris has just posted the last installment of a five-part series about the role his late brother Noel played in the invention of e-mail. In addition to being a fascinating and valuable oral history of the time-sharing era of computing, it's a moving memoir and a meditation on life's refusal to be calculable: Part 1 Part 2 Part 3 Part 4 Part 5...