Source: Dragon #358
You discovered a shorthand method for recording spells in spellbooks.
Benefit: You scribe spells in a spellbook using a shorthand that lets you transcribe faster and to occupy less space than normal. This shorthand cuts in half the time required to write a spell in a spellbook. Such spells also take up half as many pages and require half as much of the special materials normally used.
Special: The Spellcraft DC to learn or prepare a spell from a borrowed spellbook written in shorthand equals 25 + spell level.
Normal: A spellbook written with this method holds more spells and is thus worth more than a normal spellbook of the same number of pages. A wizard may take Arcane Shorthand as a wizard bonus feat.