Victoria Ward has an interesting set of thoughts on knowledge work in Like a Samurai's sword. I'm not sure of a good quote, so I'll just use her last question as an enticement to read the whole thing.
How many of us, in the conditions of urgent work which press hard down on us, find room to spend 'a week, or even weeks...accumulating powers of attention, memory and intuition'? Do we give ourselves permission? Are we given permission? Do we, perhaps need to start taking permission rather than wait for it to be given?
I am reminded of Jim McGee's Knowledge Work as Craft Work, as Victoria gives the example of craftspeople. These are people who have to study and reflect and plan before they pick up their hammers.
Knowledge work is not the work in front of the computer (or smartphone) spent typing and reading, though that certainly informs things. It is the work spent on analyzing and pondering. It is the work of making serendipitous connections to other ideas and other people. It may happen on the computer. But it might just as easily happen in the park or at a conference. (Was it HP that had those entrepreneur commercials of people getting great ideas in the shower?)
On a personal note here, I find it far too easy to attempt to think in front of PowerPoint, rather than a more appropriate location. My pad of paper and crummy drawing skills frequently break the logjam of hours.