Book excerpt: Older adults may be the world's fastest growing demographic. Yet they remain vulnerable to biases and barriers that would be intolerable if directed at others. Such an indictment puts the onus on deconstructing the idea of ageism in terms of what it means ("a riddle"), how it works ("a mystery"), why it persists ("an enigma"), and what can be done about it ("a puzzle"). Reference to ageism must go beyond the idea of a “bug” in the system. Rather, ageism is the system, the default reality of an ageist society designed by, for, and about the young and able-bodied. Ageism also intersects with other forms of identity and inequality such as gender and race to amplify the downside of getting older and being old. Initiatives for advancing a rights-based, age-inclusive society must focus on calling out ageism as a precondition for calling in a national reset.