The article gives an overview of how complex financial instruments like mortgage-backed securities and credit default swaps contributed to the financial crisis of 2007-2008. It explains how these instruments, known as structured finance, played a role in causing and spreading the turmoil. The researchers classify structured finance into two categories: those that started the crisis (MBS, ABCP, CDOs) and those that monitored it (CDS). The paper also discusses how these instruments spread financial problems between institutions.