This book studies the evolution of mortgage securitisation together with that of the derivative instruments that they have frequently been combined with. It traces the historical development of securitisation from its roots in various European legal institutions to the creation of its modern form in the U.S.A in the last decades of the twentieth century, and explores the Common Law treatment of derivatives, by explaining how they came to be distinguished from both insurance contracts and wagers. It makes the case that it was the eventual merging of mortgage backed securities with credit derivatives that resulted in securitised products acting as a catalyst for the credit crunch and the ensuing Financial Crisis, and that subsequent regulation, particularly the European Securitisation Regulation has been significantly shaped by the erroneous perception of Securitisation as a principal cause of the crisis.