Having worked in structured finance in the caverns of Wall Street, it is known that the structured finance market of CDOs and related securities can be explained and understood in a straightforward manner.  The complexity is mostly associated with the detailed mechanics of modeling and assessing risk to counterparties and investors.

Accordingly, included is a fine infographic presented by MortgageRates that helps illustrate the very basics of the CDO market.  Hat tip to Felix Salmon.