Stephen Hawking contributes his latest thoughts on the nature of space and time in this anthology of selections from Princeton University Press. Along with John Archibald Wheeler and other eminent colleagues, Hawking here extends theoretical frontiers by speculating on the big questions of modern cosmology. Beginning with a historical survey of earlier conceptions of the universe and concluding with Hawking's discussion of black holes, space-time, and quantum theory, the programme offers listeners an illuminating opportunity to grasp the magnificence of current theoretical conceptions.