Level: Wu Jen 8
Components: S
Casting Time: 1 immediate action
Range: Personal
Target: You
When you cast this spell, you increase your ability to concentrate on a spell you have already cast. You no longer need to maintain conscious concentration on the spell you cast before casting this one. Your unconscious mind maintains the required concentration, allowing you to take other actions (including movement, attacks, and even casting more spells) as normal. Short of dying, only mind-affecting spells and conditions (such as feeblemind and confusion) can affect your concentration on the other spell, though you might be convinced to willingly dismiss finding the center (and the previous spell with it) under the effect of a charm or suggestion.
Source: Complete Arcane, page 106.