We learned about this in library school, when hypertext was "Hypercard for the Mac" etc. and we all wanted one, though computerized. Nowadays, we can sorta have this, though we can't annotate it (I find myself printing out all kinds of journal articles because I can't annotate the links!). Something like the Memex, for non-fiction research books, is what I want for electronic/online books!
"As We May Think," Vannevar Bush, The Atlantic 1945.
http://www.theatlantic.com/doc/194507/bush