Comprehension

Comprehension is a Fallout 2, Fallout Tactics and Fallout 3 Perk.

Fallout 2 and Fallout Tactics
You pay much closer attention to the smaller details when reading and gain 50% more skill points when reading books.

Fallout 3
You gain one additional skill point whenever a skill book is read. However, if a skill book has already been read, the points you got from those books will not be doubled.