Flint and Steel

Flint and Steel is a tool used to place Fire in Indev, Infdev, Alpha, and Beta. It must be crafted from 1 flint and 1 iron ingot in this pattern:

Flint and steel places fire like a block when right-clicked. Fire can only be placed on top of fully solid and opaque blocks, or on the sides of flammable blocks.

A flint and steel has limited uses, but it is not a block-breaking tool and so does not lose durability from being used to hit things. If an incorrect placement is tried, it still counts as a use of the tool.

Uses
Flint and steel places fire which behaves just like any other fire. Particular ways in which this is useful are:
 * Creating portals.
 * Lighting mobs on fire. This method deals damage more slowly and is less effective than using a sword, and one must click on a block below the mob rather than on the mob itself, rendering it a difficult way to kill. However, when a pig is killed via fire it drops a Cooked Porkchop, carrying a Flint and Steel around allows a player to save their coal. Also this prevents degradation of the sword, as well as only requiring one use of the flint and steel.
 * Quickly clearing areas, by removing trees. This will save time and durability of axes.
 * Quick disposal of items, which can be accomplished by dropping the items and then lighting the block under them on fire.
 * Temporary illumination for a few seconds as the fire burns, or lighting netherrack on fire.
 * Using Netherrack and the disposal effect, an indefinite incinerator can be made without the need for lava.
 * Flint and steel, along with redstone, is the only way to activate TNT as of 1.7.

Trivia

 * In early versions of Indev, the player started with a flint and steel in their inventory. Flint and steel was also found as loot from killing mobs.
 * In the start of Survival Multiplayer, furnaces did not work. There was a mod that turned flint and steel into a "lighter" that lit the furnace and made it work.
 * Before furnaces, flint and steel could be used to smelt ores.
 * As of Beta 1.7.3, there is a glitch where it is possible to light TNT by punching it with Flint and Steel in your hand. Doing so will not consume durability of the Flint and Steel.