Arcanomicon

The Arcanomicon is an artifact created by the Titan Norgannon. It is a map of all the ley lines on Azeroth. It was given to the Blue Dragonflight aspect, Malygos, when the Titans left Azeroth.

=Nexus War =

When Malygos fell into madness the Blue Dragons continued to update the Arcanomicon and used it to monitor the ley lines and their power. When Malygos started the Nexus War he planned on using the Arcanomicon to divert the ley lines to the Nexus and use the power to stop the mortal races from using the arcane in what he thought was a reckless way. With the combined strength of the Wyrmrest Accord and the Kirin Tor, Malygos was defeated and his plans never came to full force.

Current Whereabouts
After the Nexus War it is unknown what became of the Arcanomicon. Many believe that the Blue Dragonflight are still in possession of it. Others think that the Kirin Tor might have taken it away to Dalaran in the confusion during the battle with Malygos. Neither faction will reveal any details about the  artifact, so it is impossible to know for sure.