Slow Cookers or Crock-Pots have been increasing in popularity ever since the early 1980s, especially with busy families away from home most of the day in developed countries. The slow cooker is loaded in the morning and may be left unattended all day, if set to cook on "Low." The heat emanates from the sides, and will provide a delicious meal in the evening.
The simpler cookers have an on/off switch, and the more sophisticated ones have digital, programmable thermostats. Most models have a "Low" setting and a "High" setting.
One of the best uses of slow cookers is for making the toughest kinds of meats tender. The number of uses, however, is only limited by the imagination: soups, vegetable, stews, ... even a pile of hot dogs can be throw in, and an hour or two later, they'll be delicious!
Old stoves have a recessed cooking position, often in the right rear, in which a pot can sit. This has a similar function.
See this category for Slow cooker recipes.