In a  podcast published a few weeks ago, NPR Moneys interviewed Niall Ferguson (author of The Ascent of Money,).  I summarized below some of the key ideas highlighted in the discussion:

Bank assets. Most of those assets are banks loans. It’s the money banks lent to their clients.  This means bank customers’ liabilities. Bank assets are [...]

The following interactive graphics on FT.com gives an interesting view of the weight of Bank/Finance in main European countries. This page highlights some special situation. For instance in Iceland, the total 2007 asset of the main Bank (Kaupthing) is equal to 623 % of the GDP of the country. 

 
FT.com / Video & Audio / [...]

The presentation below from Google docs explains the way Subprime worked. This is a rather complex system. But all the system bears on a very simple assumption: House prices should always increase. Of course it couldn’t work for ever.

Subprime Explained - Google Documents
 

The New York Times made a graph that shows the impact of school networking in the world of Wall Street:

This graph made me also discover Oliver Sarkozy (brother of actual french president) among the banker who will count tomorrow