Snook are a wily inshore gamefish that are caught on both the Pacific and Atlantic sides of North and South America. They generally live in mangroves, under docks and bridges, and around other types of inshore cover and structure. Their very pronounced lateral line (hence their nickname "linesiders" helps them detect prey movement even in very murky water. They can be found in both fresh and salt water and are a very popular gamefish wherever they are found.
Snook feed primarily on small fish and crustaceans like shrimp. They are ambush predators and make a distinctive "thump" when they hit a lure or bait. Once hooked, they put up a spirited fight that often includes some gill-rattling jumps and dogged runs.
Snook do not have teeth but do have a sharp gill plate you have to watch out for. They can usually be lipped like Largemouth Bass. Although often released, they do taste delicious. They are heavily regulated in most parts of the US, so make sure you are aware of local regulations on limits.
I would recommend a light saltwater spinning set up. 30lbs braid should cover most situations, with a fluorocarbon leader between 15-40lbs depending on the size of the fish and the water clarity. I generally like to use circle hooks since I release most fish. The shimano saragosa is my favorite spinning reel. Shimano makes some good round baitcasters for this type of fishing as well.