Lightly scrub the potatoes. Put them in a large saucepan with cold water to cover by about 3 inches and season generously with salt. Bring to a boil over high heat. Lower the heat to maintain a gentle simmer and cook until the potatoes are fork tender, about 40 to 45 minutes.
Drain the potatoes in a colander in the sink. Let the potatoes cool just until you can handle them--hot potatoes make better mashed. Meanwhile, melt the butter in the pan over low heat.
Hold the potatoes in a towel or in a kitchen glove and gently peel the potato skins off with a knife or your fingers. Quarter the potatoes and put then in the pan.
Heat the milk in a microwave-safe measuring cup or bowl until hot. Mash the potatoes with the butter with a fork or potato masher if you have one, until most of the lumps are gone and the potatoes are smooth and fluffy. Then stir in the milk, until the mashed potatoes are light and smooth, if there are still lumps paddle them smooth with a wooden spoon. Season with 1 1/2 teaspoons salt or to taste, and pepper, to taste. Serve immediately.
From Food Network Kitchens, How to Boil Water, Meredith, 2006