Cobbled medieval alleyways and ornate Georgian boulevards. Decadent marble mansions and sprawling Victorian slums. Heaths, churches, squares and railways that, between them, hold two thousand years of secrets: London's history is written into the very fabric of its streets. In 'Cruickshank's London', one of Britain's best-loved historians vividly describes twenty historic walks that span North, East, South and West London.