‘Homo Deus: A Brief History of Tomorrow’ is the follow-up to the hugely successful ‘Sapiens: A Brief History of Humankind’ by Yuval Noah Harari which I read last year. Having examined the development of humans in his first book through the cognitive, agricultural, scientific and industrial revolutions, Harari turns to the challenges of the future in which humans will seek to “upgrade” from Homo Sapiens to gods (or “Homo Deus”), re-engineering our physical and mental capabilities to prevent ageing, escape death and increase happiness. The impact of famine, war and plague has been significantly reduced in recent decades, to the point where we now face the opposite challenges in the form of an obesity crisis, caring for an ageing population with people living longer than ever and a world where more people commit suicide than are killed by terrorists, criminals and conflicts.

‘Homo Deus’ is essentially an expansion of the final chapter of ‘Sapiens’ but it doesn’t matter which book you read first. In order to speculate on what the future may hold, it is necessary to look at the past and some of the ground covered in ‘Sapiens’ is revisited in the first two parts of ‘Homo Deus’ through topics such as our relationship with animals and how a humanist society functions. The final part also has some overlap with this year’s winner of the Wellcome Book Prize To Be a Machine by Mark O’Connell in its discussion on the possibilities of transhumanism.

Harari is excellent at synthesising vast concepts with pertinent examples and although his hypotheses are sometimes light on detail as befits a book dealing with such broad topics, they are clearly and convincingly argued. History and science form the backbone of Harari’s research, but ‘Homo Deus’ is as much about the ethical questions surrounding the possible limits of human capability or the point at which technological development becomes problematic for humans as a species. Even for those who value quantity as much as quality of life, I doubt many would see the appeal of living in a state of immortal meaninglessness.

It is possible that there might be an algorithm one day which produces definitive answers to some of the big questions about the future of mankind that Harari explores here. For now, ‘Sapiens’ and ‘Homo Deus’ will provide rich food for thought for any reader interested in what humans will try to achieve by the end of this century. I look forward to reading Harari’s recently published third book ‘21 Lessons for the 21st Century’ which looks at the current issues facing humanity right now.