In his Histories, Herodotus tells the story of Polykrates, overlord of the island of Samos. The king of Egypt counseled Polykrates to throw away some possession of great value, lest a surplus of good fortune bring him tragedy. Heeding this advice, Polykrates pitched his most prized possession, an emerald ring, into the sea. Several days later, a fisherman brought Polykrates a fish as tribute. When the fish was cut open, it was discovered to contain the fatal ring. (Polykrates was, of course, brutally murdered soon afterward.) Herodotus's story (and book) was crafted as a parable about hubris. It is also a good parable about banking--and more generally about risk...