The ISS has been hiding in plain sight in the history of private international law since the 1920s. Anyone lucky enough to visit ISS-USA’s archives at the University of Minnesota would be astonished by ISS’s extensive engagement with virtually every aspect of transnational family law. During the first half of the 20th century the ISS left no stone untouched in an effort to devise an international socio-legal framework for cross-border family maintenance claims.