Introduction by Dan Kainen Oceans make up almost three-quarters of our planet. We are humbled by their vastness and power, and the countless varieties of creatures that live in them. There is wonder and magic in watching even the most recognizable species as they float, swim, or glide weightlessly through their element. The awe of watching the natural world up close is what I hoped to capture in Ocean. Photicular images, with their paradoxical ability to stitch interleaved images together, actually accentuate rhythmic motion--the perfect medium in which to enter this parallel underwater universe. Perhaps when you see a sea horse undulating through a kelp bed, a sand tiger shark's haunting gaze, or a green sea turtle "flying" dreamily through the dappled light, the image may act as a shifting mirror whose reflection alters your own perceptions, and you will experience what Herman Melville meant in Moby-Dick when he wrote, "Meditation and water are wedded for ever." Ocean by Carol Kaufmann I'm suspended in a globe of water. Instead of my feet carrying me forward, backward,or to the side, travel in any direction is possible by kicking 18-inch fins (45.

7-cm). Tucking my knees in, pointing my head down and exhaling, I aim for the coral reef below. Bubbles dance away from my regulator and decorate the halo of light above me. A whole school of minnows--silver sides, they're called--flit back and forth like butterflies, creating an opening for me to pass through. Scuba diving allows me into this alternate universe, 50 feet (15.2 m) below the surface of the Caribbean Sea off the coast of Belize. I've been a certified diver for nearly a decade. But for my own safety, I explore the undersea world with experienced dive masters.

They also know about the ocean, and what lives in it. Today,I'm diving with an amazing guide: Francisco Linarez grew up in a small village called Independence, close to the Placencia Peninsula where we are diving today. Francisco is a grand dive master in a country known for good diving. He regularly swims with whale sharks when they come to southern Belize each year during spawning season. The largest fish in the sea, they can reach up to 40 feet in length (12.2 m). Some years ago, a hammerhead shark swam right into Francisco's hest. He is unflappable.

I'm always a little afraid to be in the big, neverending ocean. That first big step or a backward roll off a swaying boat is a leap of courage, if not faith. But after Francisco connects my breathing regulator to the air tank, and I reassure myself that the tank truly contains breathable air, that my mask isn't leaking and salt water won't spit into my contact lenses, I suck in a big gulp of air and descend. Once I'm in that purely liquid space and shades of blue envelop every line of vision, and that first fish passes by, I know exactly what will happen. I will forget to be scared.