The book "Bridges: their engineering and planning" explains how engineers protect bridges from dangers like earthquakes and floods. It talks about different types of bridges and how engineers decide which one to build. The book is divided into four parts: Deciding about Bridges, Bridge Engineering, Bridge Planning, and Conclusion. It covers topics like understanding stresses and strains, costs and benefits of bridges, and how bridges impact the environment. The main goal is to show how engineers design and plan bridges to withstand extreme events and serve communities for generations.