My Codex Vitae (book of life) is a public, living, dying, document that I created as an experiment one Sunday in April of 2012 (see this Changelog for a full history), and has been revised at least semi-yearly ever since.
Maintaining it has become one of the most treasured activities in my life. It’s a way for me to remember who I am, catch inconsistencies in how I respond to different events in the world, react to current events from a position of how I believe the world is, should be, and will become. I’ve updated it at least once a year since 2012, and all changes are tracked. Rather than attempting to avoid all errors in this doc, I’m attempting to be as specific as possible and to quickly correct errors when they become apparent.
It often moves around, to account for my relationship to technology at the time, and what I perceive to be the best confluence of change-tracking, accountability, readability, etc. It currently lives on Github.
If you are interested in making one of your own, I recommend starting small and slowly building it up over time. Here’s the one I first came up with in 2012. Also, be patient with yourself as you slowly realize that you don’t even know what your beliefs are, and that they’re really difficult to pin down. That’s part of the fun!