The first edition of Experiencing Geometry was published in 1995. It was a result of Prof. Henderson’s 20-year experience of teaching geometry and honing his unique teaching style. While preparing 4^th edition of this book in his memory, I went through his notes and journals from the 1970’s which gave me an insight into how deeply he was thinking about meaning in mathematics. I will share some of that and will talk about Prof. Henderson’s decision to switch from a highly regarded research mathematician’s path to “educational  mathematics” (his term).