A Brief History of Time attempts to explain a range of subjects in cosmology, including the Big Bang, black holes and light cones, to the nonspecialist reader. Its main goal is to give an overview of the subject but, unusual for a popular science book, it also attempts to explain some complex mathematics. The author notes that an editor warned him that for every equation in the book the readership would be halved, hence it includes only a single equation: E = mc2. In addition to Hawking's abstinence from equations, the book also simplifies matters by means of illustrations throughout the text, depicting complex models and diagrams.