In memory of loved ones who have died whilst writing this book, including my Grandma, who had a good innings at 93, and my dearest friend Scott, who at 47 did not.

With thanks to my partner, Ann, whose support has allowed me to spend too much time at my desk researching and writing, and who’s realism has highlighted to me how hard it is to convince people that, yes, I really mean we may be able to live forever.