You can find tons of info on the web about these "kamado" type smokers. The ones I have are from kamado.com. Another very popular brand is biggreenegg.com . I think these have roots to a japanese cooker.
The shape and material (thick ceramic based) of the cooker is the secret to great bbq and grilling. The temperature is controlled using 2 vents (1 near bottom and 1 on top ). Remember the principle of hot air rises? Cool air (oxygen) enters the bottom vent to feed the burning coal lumps/briquettes/wood and hot air escapes/rises through the top vent. When the cooker is closed, hot air escapes only through the top vent. The thick ceramic sides retain heat and radiate heat to the food (convection principle). Moisture loss is minimum and the meat comes out great. It uses very little coal also due to this design. You can control temperature as low as 150f and as high as 750f+.
More than once, I've had friends over for steaks and claim my steaks are better than ruth chris'. One guy even had a steak at ruth chris' the night before.
These things take some learning & practice to master. It is not like your average bbq grill where you turn on the gas, click a button and go at it. You'll be tinkering with it the first few times to control the temp but it is not hard and the results are rewarding.
details???