The plough. WINNERS AND LOSERS: The gramophone -- Barbed wire -- Seller feedback -- Google search -- Passports -- Robots -- The welfare state. REINVENTING HOW WE LIVE: Infant formula -- TV dinners -- The pill -- Video games -- Market research -- Air conditioning -- Department stores. INVENTING NEW SYSTEMS: The Dynamo -- The shipping container -- The barcode -- The cold chain -- Tradable debt and the tally stick -- Billy bookcase -- The elevator. IDEAS ABOUT IDEAS: Cuneiform -- Public key cryptography -- Double-entry bookkeeping -- Limited liability companies -- Management consulting -- Intellectual property -- The compiler. WHERE DO INVENTIONS COME FROM? The iPhone -- Diesel engines -- Clocks -- The Haber-Bosch process -- Radar -- Batteries -- Plastic. THE VISIBLE HAND: The bank -- Razors and blades -- Tax havens -- Leaded petrol -- Antibiotics in farming -- M-Pesa -- Property registers. INVENTING THE WHEEL: Paper -- Index funds -- The S-bend -- Paper money -- Concrete -- Insurance -- Looking forward -- The light bulb.