You are holding in your hands a collection of Stephen Hawking's Reith lectures on black holes, given on BBC Radio 4. It is difficult to imagine who could talk about some of the most mysterious objects in space more interestingly and simply than the man who made cosmology a popular science and gave many years of studying the effects associated with black holes. Those questions that remained unanswered were explained by David Shukman, science editor of the BBC. The Reith Lectures, or lectures named after Lord John Reith, the first Director General of the BBC, educator and popularizer, are a series of popular science recordings. Since its founding in 1948, the studio has featured performances from Bertrand Russell, Robert Oppenheimer, Jonathan Sachs and others.