The Book of Staves, Chapter Five, verses 41 to 47:
"41 And then did the All-Father descend unto the newly-formed World, and his Glory did shine upon it. 42 With him came his stalwart companions, Thurin the Shaper, Kenaryn the Hunter, and Malog the Warrior. 43 And the face of the World was bleak and empty, and did bring no joy to they who looked upon it. 44 And so it came to pass that the All-Father sang aloud the True Name of the Horse, and so the first horse was made manifest, in the very image of the beast in His thoughts. 45 Next He called the True Name of Hound, and hound appeared. 46 One by one did the All-Father sing the Names all of the Beasts and Plants and Things of the World, and all of them were made manifest, from the lowliest Ant to the loftiest of Eagles and the Leviathans of the seas. 47 Thus did the All-Father call the living World into being, but still his labors were not doneâ€¦"
Early in the Age of Twilight, the Elvish Magi discovered that every kind of animal and beast has a True Name, and that these names hold great power. They began to divine the Names of everything in the World. So was born the Art of Summoning, a powerful branch of magic that let a Magus call creatures to him and do his bidding. Over time, the ancient Summoners learned to call greater and greater beasts, and even learned to reach out into the Void to call its denizens: the mighty Jinn, the twisted Imps of Chaos, and even the great Archons themselves. Learning the True Name of an animal or beast requires exacting study, precise divinations, and more than a little intuition. The True Names of most things in the World were recorded in great lists by the Elvish Magi of old, but unfortunately many of those records have since been lost or destroyed.
The key to Summoning is the True Name, an arcane word that does more than merely describe. True Names embody the entirety of the thing named, and when properly called thrice in succession they cannot be ignored. The Summoner focuses his will, calls the Name, and the creature that bears that name is drawn to the Caller, appearing out of the very air. To succeed in a Summoning, the Caller must be strong of Will, for most Summonings are resisted, and it is the Caller who must pull the summoned creature through to him. There are dark stories whispered of Summoners who lose these contests of will. Their minds are either broken from the strain or they vanish from the World, never to be seen again. It is difficult to call large or mighty beasts, and far harder to Call a creature that dwells found in distant lands than it is to call one in its native habitat. While summoned creatures often fall under the control of the Caller, such is not always the case. Distractions or lapses in concentration can bring a frenzied creature to the Caller, and every beast summoned resists with all his will. The mightier the creature called, the more likely it is to escape the Caller's control and lash out at everything around it in fury. "Do not call up what ye cannot put down" is the first lesson every Summoner learns, and those who reach beyond their grasp do so at their peril.
From the earliest days of Summoning, debate has raged among the Wise over the true nature of the creatures called. Does the Caller call a beast to them that already exists from somewhere else in the World, or do they actually call a new creature into being, as it is written that the All-Father did in the Book of Staves? Experiment and argument gave few answers, but shocking discoveries made since the Turning have finally given credence to the second view. It seems that when a True Name is called, the Universe itself responds by creating the appropriate beast, for some renegade Summoners claim they now have the power to create beasts that are entirely new. Many hideous beasts like the Chimera or Manticore, have been born of this new Art, called Conjuring. Curiously, some ancient records hint that similar experiments were attempted in the Age of Twilight, but that they all failed. Why they should succeed now is a mystery, and the various theories are hotly debated among conclaves of Magi. The Conjurers themselves hold their secrets close.