Inland sand dunes are widespread in North America and are found from the North Slope of Alaska to the Sonoran Desert in northern Mexico and from the Delmarva Peninsula in the east to Southern California in the west. In this edited book, we highlight recent research on areas of inland dunes that span a range from those that are actively accumulating in current conditions of climate and sediment supply to those that were formed in past conditions and are now degraded relict systems.