The onus of the blame for the financial meltdown of 2007 has often been placed on mysterious creatures known as âÃÂÃÂderivatives.âÃÂàHeidi will explain just what these Gremlins of Wall Street are, how they got to be so out of control, and what can be done to rein in their mischief. They certainly did seem cute and harmless at firstâÃÂæ