Villager

A Villager, also known by many players as a Testificate, is a passive NPC (non-player character) that spawns and moves about in NPC Villages. Their characteristic look is dominated by their large, bald heads, green eyes, unibrows, and long, protruding noses. There are different types, distinguished by the color of their robes, and signifying their role in the community. Some spawn around the village, although most spawn inside buildings and leave once the door is opened. They spawn at their respective buildings corresponding to the role they have. As of Beta 1.9 Pre-Release 3, there are 6 unique skins for the villagers which are found in the minecraft.jar file. Another, unused villager skin is a file called "villager.png" that appears to be the skin of "Steve" with some modifications.

Behavior
Villagers act more like passive mobs. They will randomly look at the player, and wander the area of the village. They do not attack if attacked, however they will be knocked back. When attacked, they will not run away like other passive mobs, and, with the exception of zombies, hostile mobs do not see them. If the player does happen to kill one, they drop nothing. They will leave buildings if the door is open and randomly wander outside. They used to have the same AI programming as a Pig, although they cannot be led by wheat.

However in Snapshot 12w05a, Villagers gained the ability to utilize doors and therefore use houses. Since Snapshot 12w06a villagers will now hide in houses during night or rain and will also run away if they see a Zombie, which now attacks the villagers. They will also "socialize" with each other and passive mobs. This involves two villagers simply facing each other.

In Snapshot 12w07a, Villagers will mate depending on available housing. The amount of housing can be supplemented by the player creating enclosed structures with a roof and door. The villagers seem to keep the population equal to half the amount of houses available. The type of villager that the child is, doesn't seem to depend on what type the parents are; Two regular brown robed villagers can have a child that is any of the occupations. Unlike other breed-able, non-tameable mobs, the parents and child have no interaction. Instead, they will quickly move about the town, entering and leaving houses at will, likely due to the increased speed of being a baby combined with the Villager AI in general. The baby Villagers will also chase each other around the Village to simulate that they are playing tag.

Professions
Each Villager's profession can be identified by its clothing: (Note that all Villagers have brown clothing under their robes/aprons)

History
Villagers were first introduced in Beta 1.9 Pre-release 1. They had "TESTIFICATE" over their heads the same way player names are applied in Multiplayer, which was removed in Beta 1.9 Pre-release 2.

As of 1.1, the original Farmer NPC can be spawned in Creative mode by using Spawn Eggs. The other NPC variations may be available in the future.

In 12w05a, villagers can open and close doors, go inside at night, and can detect villager houses.

In 12w06a, villagers can socialize with each other and passive mobs, are attacked by and run away from zombies, and go inside when it rains.

Future
It has been confirmed that there will be more villager AI applied in a future update. This has been fully confirmed during the development phases of Minecraft 1.2, when villagers slowly gained knowledge snapshot by snapshot.

Villagers are most likely to have sieges against zombies. This means that villagers will have some sort of way of defense or weapons.

Trivia

 * Since the Villager's introduction, there has been a texture in the game files indicating a standard Villager type due to their filename. However, this role seems to be filled by the Farmer type instead, with no Villager of this type ever spawning.
 * A texture in the main mob directory of Minecraft appears to be the default character texture ("Steve") reoriented to be a Villager texture. As is expected, applying it to the current Villager model produces a very broken look, as seen above.
 * Villager's arms are implied to be jointed, with two parts each to create folded arms. Another likely implication is that the arms are tucked inside the sleeves of the robes (or shirts for blacksmiths and butchers) so that the sleeves touch.
 * It has been proven that Villagers can climb ladders if they are in their path, like other mobs
 * Due to their peculiar look villagers have been ridiculed by the fanbase, sometimes comparing them to Squidward from SpongeBob SquarePants or Bert from Sesame Street. Notch himself agreed they look like "caveman Squidwards".
 * Villagers do not drop Experience Orbs once killed.