Cosmology the study of the universe arouses a great deal of public interest with serious articles both in the scientific press and in major newspapers with many of the theories and concepts e.g. the big bang and black holes discussed often in great depth.Accordingly the book is divided into three partsPart 1 The whole story presented as far as possible for a nontechnical readerPart 2 The same story told again but for a reader with some technical knowledgePart 3 Appendices with full technical details of several of the important topics covered.Part 1 is readable and understandable by anyone with a nodding acquaintance with the basic language of cosmology events lights paths galaxies black holes and so on. It covers the whole story of the book in a way as untechnical as possible given the scope of the topics covered.Part 2 covers the same ground again but with enough technical details to satisfy a reader with basic knowledge of mathematics andor physics.Part 3 consists of appendices which are referred to in the other parts and which also contain the highly technical material omitted from Section 2.