Another benefit of using physical books for my research is the handwritten notes I keep in notebooks, which form the backbone of my writing. I date every note I take and use them to check quotes or references. The system also helps me retain the information better. (Read more about that here.) I often write the first draft of books and essays by hand. That may not seem efficient, but formulating abstract concepts across industries, markets, life situations, as I do, requires a mental workout with the material that I can only achieve on paper. I try to transcribe my drafts and notes as quickly as possible to make a backup, edit the text, and organize it into the overall structure of the finished work.