This document summarizes the history and status of research on structure-soil-structure interaction (SSSI). It discusses early analytical research from the 1970s studying the interaction between two structures through soil. It also describes numerical modeling research from the 1990s onward using methods like finite elements. The document notes that while SSSI research has made progress, models still often oversimplify soil and structure properties. Future research is needed to develop more realistic models of the complex SSSI phenomenon.