The Death Note is a central plot piece in the anime and manga series, Death Note. The object itself is in the form of a notebook, with the words "Death Note" written in various languages. Used by Shinigami, the Death Note's principal purpose is to cause death to those whose name is written within it. In the series, one such note is used by Light Yagami to kill off criminals under the alias of "Kira".
Death Notes are the tools used mainly by Shinigami (commonly dubbed Gods of Death). If a Shinigami kills a human with his or hers Death Note then the remaining life span of that human is given to the said Shinigami, as long as a Shinigami keeps killing humans they can live forever without being killed by things such as guns and knives. Each Shinigami is only allowed to have one Death Note in their possession, any more should be given back to the Shinigami King. However the series main shinigami - Ryuk - came into possession of a second Death Note by tricking the Death King. Another Shinigami named Rem also comes along a second Death Note to which was another Shinigami (Gelus) whom had killed himself in order to save Misa Amane.
 Clauses of Use
The Death Note has many ulterior, effects mostly on the user. These include the advent of going to neither heaven nor hell when one dies. Another notable effect of the Death Note is the nightmares one experiences after using it. These visions generally consist of bodies of those killed with the Note's power somehow terrifying the user. Ryuk says that these visions could make one insane, a fact which Light rebuffs, saying he is strong enough to withstand such things.
When writing a name in the Death Note, certain rules must be followed. In the note itself, they are written in english, as that is the most universal language. Some of the basic rules include:
If the time of death it written within 40 seconds of writing the cause of death as a heart attack the time of death can be manipulated and the time can go into effect within 40 seconds after writing the name
The human who becomes the owner of the Death Note can in exchange of half of his/her remaining life get the eyeballs of the god of death which will enable him/her to see a humans name and remaining lifetime when looking through them
 Users of the Death Note
L (Live Action Films only.)
Taro Kagami (Manga Pilot only)
C-Kira (Manga only)
This is a list detailing all the Shinigami known/seen using their Death Note at some point during the anime or manga.