The changing thickness of manuals

[John Galt]

Nearly every time I picked up a manual to look up a function or learn how to do something, I would learn completely unrelated things I wasn't looking for. Leafing through a manual would invariably cause me to stumble upon things I would remember later: "oh, that's a better way of doing what I wanted to do."

PDFs are no substitute for developing that kind of knowledge. They excel only at searching for something you already know exists.