What will be the most important problems of the next 50 years? When we think we've found one, how do we know if we're mistaken? Which problems are being overlooked? Which global trends will continue, and which will break?

The Horizon Library Project was created by Impact Books in conjunction with employees of Open Philanthropy, which has also provided the funding for this project. Open Philanthropy is a research and grant-making organisation that tries to identify and make progress (when possible) on questions like those above. Their, and our, interest in this kind of inquiry is driven not just by intellectual curiosity, but by altruism: Open Philanthropy has found these questions to be very relevant to making the very best grants, as they work to maximise the expected good they do.

These are some of the writings which Open Philanthropy has found most useful to their thinking about big problems and the future. They include books on nuclear and biological weapons, on the potential and risk of artificial intelligence, on global poverty, and on how to evaluate arguments in areas where your intuition offers little guidance. Neither Open Philanthropy nor Impact Books agree with every idea or argument in these books. But we do think all the ideas are important, and deserve to be more widely read and argued about.

We hope you enjoy you free book: