Preface To The Third Edition – Acknowledgments – From Cave To Skyscraper – Building A Tent – What Is A Beam? – What Do We Build Structures With? – The Floor Of Your Room – A Steel Frame … Made Out Of Paper – The Part Of The Building You Don’t See – What Tornadoes, Earthquakes, And Changes In Temperature Can Do – How To Fight Tornadoes And Earthquakes – Ropes And Cables – Sticks And Stones – Strings And Sticks – Shape And Strength – Barrels, Dishes, Butterflies, Bicycle Wheels, And Eggs – Balloons … And Back To The Tent .