This article provides a brief history of key developments in the growth of the Lausanne Trilogue Play (LTP) paradigm that paved a foundation for new scholarship featured in the papers that follow. We outline core, foundational elements of the LTP work, highlighting the close interplay between clinical and research applications, the systems orientation in both regards, thedual attention to both top down (metamodel) and bottom up (microanalysis, in particular) frames, and the relevance of transitions from dyad to triad. Next, later developments in methodological refinement and expansion within the LTP’scountry-of-origin are described, with closing commentary provided on the path-breaking contributions of severalinvestigations that employed the LTP in five different countries, each illuminating previously under-studied familyphenomena. The historical considerations spotlighted in this article, and the lessons learned from new empirical investigations the early work has inspired, are important to consider in tandem as the field begins expanding beyond the LTP’s original foundations and makes increasing use of the paradigm as a research instrument beyond clinical settings.