Kosher salt by John Spottiswood.

This salt was developed for the preparation of kosher meats, but many cooks prefer it over table salt. It has coarser grains, so it's easier to use if you, like professional chefs, toss salt into pots with your fingers, measuring by touch. Most kosher salt is also flaked, giving each grain a larger surface area. This helps the salt adhere better, so it's great for lining margarita glasses, and for making a salt crust on meats or fish. Kosher salt also is preferred over table salt for canning and pickling. Like pickling salt, kosher salt is free of iodine, which can react adversely with certain foods. Some brands of kosher salt contain yellow prussiate of soda, an anti-caking agent, but unlike the anti-caking additive in table salt, it doesn't cloud pickling liquids. The only drawback to using kosher salt for pickling or canning is that the grains are coarser and flakier, and can't be packed as tightly into a measuring cup as pickling salt. This raises the risk that the salt won't be properly measured. To get around this problem, measure by weight instead of volume. With its large grains, kosher salt isn't a good choice for baking. Look for boxes of it in the spice section of your supermarket.