6Humans have been building bridges for centuries. They have opened up new areas to exploration and commerce. Although the basic function of bridges has not changed, the materials and methods of construction have undergone amazing transformations over the years. These continue to advance, which will allow engineers to make bridges that are even longer and sturdier than the ones that exist today. Informative sidebars enhance the engaging main text, giving readers an in-depth look at the history and science of bridge construction. A glossary of new terms gives readers a better grasp of the subject matter, and a list of websites gives a starting point for further research.