This is a new introduction to AI as an extinction threat, previously posted to the MIRI website in February alongside a summary. It was written independently of Eliezer and Nate's forthcoming book, If Anyone Builds It, Everyone Dies, and isn't a sneak peak of the book. Since the book is long and costs money, we expect this to be a valuable resource in its own right even after the book comes out next month.[1] The stated goal of the world’s leading AI companies is to build AI that is general enough to do anything a human can do, from solving hard problems in theoretical physics to deftly navigating social environments. Recent machine learning progress seems to have brought this goal within reach. At this point, we would be uncomfortable ruling out the possibility that AI more capable than any human is achieved in the next year or two, and we would be moderately surprised if this outcome were still two decades away. The current view of MIRI’s research scientists is that if smarter-than-human AI is developed this decade, the result will be an unprecedented catastrophe. The CAIS Statement, which was widely endorsed by senior researchers in the field, states: > Mitigating the risk of extinction from AI should be a global priority alongside other societal-scale risks such as pandemics and nuclear war. We believe that if researchers build superintelligent AI with anything like the field’s current technical understanding or methods, the expected outcome is human extinction. “Research labs around the world are currently building tech that is likely to cause human extinction” is a conclusion that should motivate a rapid policy response. The fast pace of AI, however, has caught governments and the voting public flat-footed. This document will aim to bring readers up to speed, and outline the kinds of policy steps that might be able to avert catastrophe. Key points in this document: * There isn’t a ceiling at human-level capabilities. * ASI is very likely to exhibit go