If you like your smartphone or your widescreen TV, your car or your pension, then, whether you know it or not, you are a fan of Wall Street. William D. Cohan, bestselling author of House of Cards, has long been critical of the bad behaviour that plagued much of Wall Street in the years leading up to the 2008 financial crisis, and, as an ex-banker, he is an expert on its inner workings as well.But in recent years he has become alarmed by the vitriol directed at the bankers, traders and executives who keep the wheels of our economy turning.Why Wall Street Matters is a timely and trenchant reminder of the dire consequences for us all if the essential role these institutions play in making our lives better is carelessly curtailed.