A few years ago I tried to find information related to OOP from the source, the person who coined the term. However, probably because I didn’t search good enough, I just move on … but today reading Jason Brennan's blog I find a post which redirects me to this incredible piece of history.
Basically it's the correspondence between Stefan Ram and Alan Kay where Dr. Kay describes the history behind the OOP idea and the concepts he considers relevant.
Plase read the correspondence and allow me to quote a little part of it :)
My math background made me realize that each object could have several algebras associated with it, and there could be families of these, and that these would be very very useful