Mimir (pronounced “MEE-meer;” Old Norse Mímir, “The Rememberer”) is an exceptionally wise being and a counselor of the gods. From the surviving sources for information on Norse mythology, it’s impossible to tell whether he was considered to be an Aesir god or a giant.
Mimir was killed and beheaded by the Vanir during the Aesir-Vanir War. Upon seeing the severed head, Odin embalmed it with special herbs and chanted magical songs over it to preserve it. He consulted the head in times of need, and it continued to dispense incomparable advice.
More than any other being in Norse mythology, Mimir seems to be regarded as the divine animating force behind the wisdom of past tradition and its indispensable value as a guide for present actions.
 Simek, Rudolf. 1993. Dictionary of Northern Mythology. Translated by Angela Hall. p. 216.
 Bauschatz, Paul C. 1982. The Well and the Tree: World and Time in Early Germanic Culture.