Ten of the best doppelgängers

At the Guardian, John Mullan named ten of the best doppelgängers in fiction.One novel on the list:Despair by Vladimir NabokovHermann Karlovich, a Russian businessman, tells how, in Prague, he meets a tramp called Felix who looks exactly like him. Hermann suggests a switch of identities - and then murders the gullible Felix for his own life insurance. The perfect crime. Except that the exact