I’d been doing it for decades before I discovered there’s a name for the practice. It’s a hard habit to break, since it grows only more compelling with time and repetition. It’s still relevant, though, and still favoured by those enamoured of the printed word. It’s called keeping a commonplace book.  

The practice consists of hand-copying passages from your reading into personal notebooks, sometimes along with your written responses. Devotees of the word have been doing it for centuries, and they’re doing it still. What I had always imagined was a personal quirk, turns out to be a time-honoured tradition, and among writers, even a sort of method. 

It's not too much to say that I learned to write the commonplace way. You can, too.