In this deep dive session from AWS re:Inforce 2022, Becky Weiss provides a comprehensive look at AWS Identity and Access Management (IAM) from first principles. She explains the core concepts of IAM, including the separation of control and data planes, static stability, and how authorization works across AWS services. Weiss walks through the step-by-step process of how IAM evaluates requests, covering topics like authentication, policy evaluation, and cross-account access. The talk aims to give viewers a deeper understanding of IAM's inner workings, enabling them to write more effective policies and better secure their AWS environments. With practical examples and insights from her experience at AWS, Weiss offers valuable knowledge for anyone looking to master IAM and improve their cloud security posture.