This document summarizes Dr. Charles Severance's work over 20 years to promote open standards and interoperability between learning tools and systems. It shows his involvement in early online learning projects in the 1990s, the development of the Learning Tools Interoperability specification in the 2000s, and his role in evangelizing Simple LTI and Basic LTI to achieve widespread adoption across both open source and proprietary learning platforms by 2010. The overarching goal was to empower teachers and learners by giving them more choice and control over the tools and technologies used for teaching and learning.