I spent summers as a young child and teenager living with my grandparents in an enchanting, small town called Budingen, located an hour's drive from the metropolis of Frankfurt. Each summer, I was transported from the strip malls of southern California to the small forest-covered region of postwar West Germany. Budingen was the county seat, and my grandfather, Kurt Moosdorf, served as county executive or Landrat, for more than 25 years. As Landrat, my grandfather oversaw local government, including the economic development and public infrastructure projects that were part of Germany's postwar economic miracle.

My grandparents’ house overlooked the local Sparkasse. The Sparkasse was often the first stop my grandmother and I made each morning on our groceryshopping rounds. She would chat with the staff, check her account, or pick up a deposit receipt. It seemed normal for her to know everyone in the bank. Several decades later, I realized the reason she knew everyone at the Sparkasse was that her husband, the Landrat, was the first line of supervision and governance in Germany's public savings banks. My grandfather chaired the supervisory board of Budingen's Sparkasse for more than two decades, and it was my grandfather who oversaw the banks’ construction.

When I visited the Sparkasse in Budingen in 2018, I learned it had merged and become part of a larger county system. The building was newer, the layout was different, and ATMs dotted the lobby. The name and brand were similar though: a giant recognizable red “S” with a dot over the top. I wanted to know how this institution, which had played such a central role in my grandfather's life and the life of Germany, had evolved and developed. It seemed to be thriving and I wondered why. How could a small local financial institution, governed and overseen by local politicians no less, survive global capitalism and privatization? What was going on?

Politics is another driver for this book. Three recent global challenges underscore Sparkassen's significance. The first is the Great Recession of 2007/08. For more than 200 years, Sparkassen have been at the centre of Germany's model of capitalism.