Thinking and computer screens

I belong to a number of mailing lists and on one recently there was a discussion of digitising textbooks. In the light of that I wish to make a few comments. 
I work with computers all the time, 3/4s of my waking hours are spent in front of a screen, so I am used to computers. However when I need to read important documents that I have to cognitively engage with, I need it in printed format in my hand. I have had to review journal articles, and edit book and thesis chapters – small formatting functions can be seen on screen but not faults of conceptual design. 
I think the rush to computer screen needs to be done with great care.