Your wisdom is the combination of what you have experienced and what you have reflected on.
Studies show that people forget 50% to 70% of new information within a day.
How much wisdom is lost because people don’t record what they learn and their reflections on what they learn?
Your personal book of knowledge is your way of memorizing new information and your reflections on that information. After a while, your PBOK is going to have a wealth of information that will lead to an increase in wisdom.
I encourage you to find a system for recording your experiences and reflections to start building your personal book of knowledge.