Microsoft President Brad Smith operates by a simple core belief: when your technology changes the world, you bear a responsibility to help address the world you have helped create. This might seem uncontroversial, but it flies in the face of a tech sector long obsessed with rapid growth and sometimes on disruption as an end in itself. Now, though, we have reached an inflection point: Silicon Valley has moved fast and it has broken things. A new understanding has emerged that companies that create technology must accept greater responsibility for the future. And governments will need to regulate technology by moving faster and catching up with the pace of innovation that is impacting our communities and changing the world. In Tools and Weapons, Brad Smith takes us into the cockpit of one of the world's largest and most powerful tech companies as it finds itself in the middle of some of the thorniest emerging issues of our time. These are challenges that come with no pre-existing playbook, including privacy, cybercrime and cyberwar, social media, the moral conundrums of AI, big tech's relationship to inequality and the challenges for democracy, far and near. While in no way a self-glorifying "Microsoft memoir," the book opens up the curtain remarkably wide onto some of the company's most crucial recent decision points, as it strives to protect the hopes technology offers against the very real threats it also presents. Every tool can be a weapon in the wrong person's hands, and companies are being challenged in entirely new ways to embrace the totality of their responsibilities. We have moved from a world in which Silicon Valley could take no prisoners to one in which tech companies and governments must work together to address the challenges and adapt to the changes technology has unleashed. There are huge ramifications to be thought through, and Brad Smith provides a marvellous and urgently necessary contribution to that effort.