Inspired by this passage from Michael Shea's Nifft the Lean (p.29):
"Come nearer, and I will put in your memory the manner of your coming, and the spell."
My friend put his ear to her lips. She whispered for a long while, and my friend looked outward as he listened, but you could see from the dazed shifts of his eyes strange spaces opening up in his mind.
Urdustin's Mnemonic Exchange
[aka Bestow/Receive Mnemonic Contents]
Level: Wiz 5
School: Incantation; Metamagic; Mnemonic Science
Author: Urdustin of the Long Memory*
Rarity: Common in civilized and barbarous areas
Casting Time: See below
Components: Verbal, Psionic**
Range: Hearing distance (varies with acuity of listener)
Save: Only necessary if target wishes to resist
This spell creates a psionic channel between the wizard and a single target listener. Any others within hearing range will not be able to comprehend the sounds being uttered. Other magic-users, perhaps scrying the scene from afar, will be able to identify that Mnemonic Exchange is being used, but will be unable to determine the content of the exchange.
Through the temporary mental bond created a wizard may send any number of memories (including memorized spells, with some limitations) into the target's mind. Such transfers require time and the wizard's full concentration. A 1st level spell takes 1 turn (10 minutes), a 2nd level spell takes 2 turns, and so forth. Spells higher than 5th level will inflict 2d6 damage to the target's brain as they physically re-organize it to properly accommodate themselves (ignore this rule if target is a magic-user of at least three levels of experience).
Other types of memories -- mental images, scenes and other data acquired through the senses -- may be transferred at a rate of 1 turn per hour of mnemonic content. Most concepts and solitary images take significantly less time to impart. In such light-volume cases, ESP or spells with ESP-like effects would be used in this spell's stead.
The reverse of this spell copies information from a target's mind into the mind of the wizard. The rates of transfer are identical to those outlined above.
More complex variants*** of this spell allow the wizard to alter the subject's memories -- adding, changing and annulling information according to his design.
Mnemonic Exchange has been used to raise the intelligence of beasts and teach them the use of language.
*Most modern wizards are 85% likely to consider Urdustin to be a mythological figure similar to Hermes Trismegistus. His name is widely recognized in magical circles and carries a note of ancient tragedy.
**Psionics are an underlying part of many forms of magical inquiry and practice. It is considered the foundation of the school of Illusion, for instance.
***See Anteleoch's Secondary and Tertiary Adjustments