Button

A button is a switch. Like levers, pressure plates, and tripwire hooks, it sends a redstone signal to adjacent blocks when pressed. However, a button can only be activated by being pressed and will only stay pressed for 1.0 seconds (10 repeater ticks). After this, the charge to the object will be lost and the button will pop out, ready to be clicked again. However, with the creation of a T Flip-flop redstone circuit, it can be used as a lever substitute. Unlike levers and torches, a button can only be placed on the side of a block.

Like any object that gives charges, it must be next to the object receiving the charge (doors, rails, etc.) or connected to it by a length of redstone wire.

The button is one of five switches currently in the game. As a momentary-contact switch, it can be useful for resetting redstone circuits.

When submerged in water, Buttons are destroyed, rather than merely becoming unattached, like torches.

Also like torches, buttons can be placed to a side of a chest, dispenser, workbench, or furnace in the same fashion. This is done by placing a solid block above the area the button will attach to, and right clicking it on the bottom with a button in hand. The button can't attach to the bottom of blocks, and will relocate to an available space. This lets you place the button on a block's side without right clicking it.

Mobs (excluding the player) cannot press buttons.

Natural occurrence
Buttons can be found naturally in Strongholds right next to iron doors.

Crafting
Buttons are crafted by placing two stone blocks in a vertical row anywhere in the crafting grid.

History
The Button was introduced in the Seecret Friday Update 3. The Button appears in Alpha, Beta and the game's Full Release.

Since Beta 1.5_01, it appears that the hitbox for the button is off. You need to click a space in front of the button for it to be pressed. This was fixed in 1.6.6, with the side effect that you cannot punch through doors anymore.

On servers, lag could cause buttons to stick for longer than their intended time. This issue was fixed in the fifth 1.9 pre-release.

Wooden Buttons were added in snapshot 12w34a. They could be triggered by arrows as well as players.

Trivia

 * When sitting in a minecart and looking down at a slight angle at a button, sometimes you cannot press it even though it is in the crosshairs. This is caused by the hitbox of the minecart.
 * 99.414% of the stone is lost in making the button, since 1 button takes up 6x2x4 pixels and 2 stone blocks take up 16x16x32 pixels.
 * Since buttons have the same color as stone, buttons can be placed on stone to make "hidden" switches.

Knopf Bouton en pierre Button Stone Button/ko Przycisk Кнопка 按钮