Underwater, the breadth and variety of the visual imagery that awaits divers and snorkelers is simply beyond description. And, to be sure, “reef” in this sense is a broad term, which can apply to environments in waters both warm and cold, salt and fresh. Photographically, some places are so magical that randomly pointing and shooting would almost be enough to capture a treasure-trove of images. In others, there is the search for and capture of something truly unique that is so special. And, particularly, when the scene involved is created by gatherings of aquatic life, or interactions between people and the aquatic world, the pictures that result can be remarkable.