Eliezer Yudkowsky is an American artificial intelligence researcher, writer, and self-taught theorist widely regarded as one of the founding voices of the modern AI safety movement. A co-founder of the Machine Intelligence Research Institute (MIRI), he has spent decades working on the problem of building AI systems that are safe and beneficial to humanity. He is the author of "If Anyone Builds It, Everyone Dies", as well as the enormously popular online work "Harry Potter and the Methods of Rationality". Yudkowsky is also known for his influential essays on rationality, decision theory, and existential risk, many of which appear on LessWrong.