Misinformation and disinformation have emerged as paramount societal challenges, affecting areas from public health to climate change and eroding both social understanding and democratic values. Enter the political fact-checkers: stalwart defenders of accurate public information and guardians of robust public discourse. What began as an endeavor to verify political claims in the U.S. has transformed into a global movement addressing diverse forms of public information, harnessing innovative tech tools, championing media literacy, and exploring governance solutions. Who are these fact-checkers, and how have they become such a versatile force against misinformation? While united by very similar verification practices, the community of fact-checkers is remarkably diverse. Reflecting the media-political landscapes they navigate, these initiatives bring together a spectrum of professional expertise, visions, and strategies. This book delves into this fascinating world, exploring how the concept of fact-checking has proliferated globally. Spotlighting efforts in Argentina, Georgia, Italy, and the U.S., it offers an in-depth understanding of fact-checkers' approaches, their alignment with distinct environments, and their potential impact on modern public discourse.