How this book came about

The origin of this book was a request by Brian Pippard to contribute a survey of astrophysics and cosmology in the twentieth century to the three-volume work that he edited with Laurie Brown and the late Abraham Pais, Twentieth Century Physics (Bristol: Institute of Physics Publishing and New York: American Institute of Physics Press, 1995). This turned out to be a considerable undertaking, my first draft far exceeding the required page limit. By drastic editing, I reduced the text to about half its original length and the survey appeared in that form as Chapter 23 of the third volume.

I was reluctant to abandon all the important material which had to be excised from the published survey and was delighted that the Institute of Physics agreed to my approaching Cambridge University Press about publishing the full version. The Press were keen to take on the project, with some further expansion of the text and, in particular, with a number of explanatory supplements to chapters where a little simple mathematics can make the arguments more convincing for the enthusiast. I have also made liberal use of references to my other books, where I have already given treatments of topics covered in this book. The result has been a complete rethink of the whole project and an expansion of the text by a factor of five as compared with the original published version.