Engineer

"'Like this heavy caliber, tripod-mounted, little 'ol number designed by me... built by me... and you'd best hope... not pointed at you.' - The Engineer"

The Engineer is one of the 9 classes that players may choose from in Team Fortress 2. He belongs to the Defensive group of classes.

Description
This amiable, soft spoken good ol' boy from Tiny Bee Cave, Texas loves barbeque, guns and higher education. Natural curiosity, ten years as a roughneck in the West Texas oilfields, and eleven hard science PHDs have trained him to design, build and repair a variety of deadly contraptions.

Only lightly armoured, the engineer wears a construction hat, team-coloured shirt, and black overalls. He speaks with a southern American accent. Engineers are used to defend bases and passageways, as well as to supply and transport the team.

The engineer is able to build various structures through "metal" points to support the team: a sentry gun that can be upgraded through three stages of effectiveness, a teleporter matrix consisting of an entry and exit facility, and a dispenser that gives team-mates ammunition and health. While its ammunition supplies are infinite, the dispenser requires time to regenerate metal supplies. Metal is collected from resupply points, dispensers, the weapons of fallen players, and even the debris of destroyed structures.

The Engineer also carries a shotgun when he needs to defend himself without the help of a turret. The Engineer's wrench can also be used as a melee weapon.

Meet the Engineer
The Engineer was one of six classes previewed by the "Meet the Classes" ad campaign ran by Valve. In it the Engineer strums a guitar and discusses his Sentry Turrets whilst they slaughter several opponents attempting to approach him. 

Tactics

 * There are key points in every map where Sentry Turrets, Dispensers and Teleporters are usually placed. It is worth playing as a different class first to note where these places are before attempting to use the Engineer.
 * The Engineers' worst enemy is the Spy, who will usually spend a lot of his time attempting to sap the Engineers' Sentries and assassinate the Engineer himself. Be on the look out for fellow team members acting suspiciously.  You can eliminate Electro-Sappers (and Spies) by hitting them with your Wrench. Make sure you hear, "Spies sapping my senty".
 * You must also watch out for Demomen, who will blow up your Sentry using sticky bombs if they are allowed to. You can shoot stickies away with your pistol, or you can try attacking the Demo with your shotgun, which causes the stickies to vanish if he is killed.
 * A good partner for the Engineer is the Pyro as they can "check" suspicious teammates who go near your turret, and also use their airblast to deflect explosives away from your buildings.