Still selling briskly at 50, “On the Road” “has far outlasted many other cult classics. Part of the reason for the novel’s staying power is that popular artists keep referencing it. (A new movie version, directed by Walter Salles, who made ‘The Motorcycle Diaries,’ is scheduled to go into production early next year.) Everyone from Bob Dylan to the Beastie Boys has been inspired by Kerouac. … But keeping it on hand can be difficult: among book-world insiders, ‘On the Road’ is known to be a heavily shoplifted work….”