The credit crunch is affecting every investor and every consumer, every industry and every government program, yet few people truly understand how it happened. Subprime mortgages have been center stage, but behind the scenes a conspiracy of greed among bankers, investors, rating agencies and regulators has imperiled everyone's financial future. We need to know what went wrong and how to change the practices that led to this calamity.

Bloomberg columnist Mark Gilbert shows how Wall Street's tolerance for extremes made the global credit crunch both foreseeable and inevitable. He offers a blow-by-blow account of what went wrong and what lessons need to be learned from the crisis.