The global human population is projected to reach more than 10 billion by the end of the century. Worldwide there are an estimated 50 million km of public road. More people mean an ever increasing human footprint as existing infrastructure will need to be dramatically upgraded to accommodate increased volumes of human use. In recent decades our science understanding of the impacts of human infrastructure, such as roads and highways has expanded greatly. We have learned of the importance of protecting areas where wildlife species can escape human harassment and injury. However, we have equally learned of the importance of making the areas in-between these protected areas more permeable to wildlife movement. Habitat connectivity is the degree to which habitat promotes or hinders species movements and dispersal. Areas with poor habitat connectivity can impede ecological processes, increase the risk of species extinctions, and reduce genetic diversity. Maintaining and restoring habitat connectivity is essential to the conservation of biological diversity, in particular, in an era of rapid climatic change. Fortunately, the science of habitat connectivity has evolved tremendously in the past few decades. Making that science available to practitioners is the focus of this book.