Philosophical speculation and science fiction are united in this: what is now obvious is most likely to be false, or at best a transient mode of being. In exploring future possibilities, the author introduces science fiction writers and contemporary philosophers alike to the riches of their twin traditions. What is the likely future of our species? What sort of global religious feeling is likely to prevail? How far can we go in engineering living artefacts, or our own descendants? Are we on the cusp of a new reality, in which we shall have to choose how human we will remain, what seemingly obvious feelings and beliefs need to be revised or re-imagined? Is it even possible that we are living out a dream, devised by the last intelligences in the last days of the universe? What now exists seems to most of us to be obvious, or even eternal, but the truth is otherwise: even our most trusted intuitions and our most stable institutions (as they seem) could have been entirely different, and may be different again. Our ordinary life may be a dream and a delirium, as ancient philosophers thought, and our chief task is to wake up.