Long infamous for its severe inequality, infant mortality, and clientelist politics, Brazil in the late 20th and early 21st centuries improved the health and well-being of its populace more than any large democracy. Christopher L. Gibson sheds light on the previously poorly understood cause of this shift, arguing that it was due to a subnationally-rooted process driven by civil society actors, namely the Sanitarist Movement. Gibson improves our understanding of the political and social trajectory of Brazil and similar democracies today.