Many fields of scientific research derive their excitement from the fact that they are totally new avenues of investigation. Other areas are remarkable for their longevity and their ability to continually generate new developments. The topic of this special issue, 3-D Sensing for Inspection, falls in the latter category. Three-dimensional sensing has been an active area of study since the earliest scientific endeavors in optics. The collection of papers in this issue attests to the continued vitality of the field today. The reason for this success perhaps stems from the fact that it is being driven by critical fundamental scientific needs as well as by ever-expanding technological applications. The papers assembled here address both of these areas.