Early in my career, I had a mentor that forced me to carry around a bound notebook and take notes on the things he showed me. At first, I resisted — I was confident in my abilities and my memory. But, he insisted. Over time, keeping good notes became a habit. Then, one day, I needed to recall a command that I knew I had run before. Sure enough, I had it in my notebook. No need to re-read a manual and reconstruct the command line. I had it captured in my notebook. I still keep a notebook and I have year’s worth of condensed knowledge in those books. They provide an excellent and accessible resource. Those books capture failures as well as successes; I’m more efficient and effective thanks to my notebooks. Frequently referenced pages are bookmarked for quick access. Additionally, I can look back on my career and analyze my development. Today, I require my mentees to take notes.