The Campfire, added by TMI, is an alternate source of light that better evokes the sense of being outdoors than the traditional Torch. However, though its dependability is worse than that of the torch.
A wooden Campfire can set nearby blocks alight, but a stone campfire only sets blocks above alight.
Walking into a campfire will not set the player on fire, though, making the Campfire a safer alternative to the traditional flaming Netherrack.
To relight a Campfire, right-click it with coal. In Minecraft version 1.7.10, right-click it with a torch. To put it out, do the same with a bucket of water. Note that rain and water blocks will not put out Campfires, which are water-resistant.
Note that the regular Campfire must be made in the top two rows of the crafting grid.
One can make an unlit Campfire by removing the stick from the crafting recipe.