After dinner today I told Brenda that I wanted a network map of all papers ever written so we could see where the biggest gaps in human knowledge were. In moments she had us browsing the site well-formed.eigenfactor.org looking at a coarser approximation of my dream (see picture).
I highly recommend any academic or casual intellectual browse the highly interactive site, it is simply too interesting, beautiful and [maybe] important to ignore.
Perhaps the two most striking observations one can make from simple visual inspection are that (1) biologists write a lot of papers and (2) social sciences/mathematics/computer science are extremely insular (observe the big "hole" in the network picture).
I'll let the data speak for itself (please please look at the site); but the only thing I'll say is that if anyone wanted to create a new field, bridging the social and physical sciences looks like a conspicuously good place to start.