Tony Hirst put me on to Graphviz, in particular the neat way of assembling the data in a spreadsheet and then exporting it to a text file in order to get the required xxxx.dot input file.
I'm playing with this as a way of looking at the relationship between the different authors, the different academic fields (philosophy, physics, semiotics...), and the different topics (knowledge, entropy, signs...) relevant to information. Of course, all these categories are problematic for all sorts of reasons (what's the difference between an academic field and a topic being one that jumps out at you) but nevertheless it seems useful to try different categories out and see where it leads.
One particularly handy feature is that it is easy to associate web links with nodes in the graphs, so you can have further information 'behind' any node.
Here's where I've got to. Names in red text are clickable - I would have underlined them, but it seems Graphviz have not inplemented an underlined style.
OK, so there's some way to go before it is really anything useful, but I think it shows promise.