That can be pocketed; of a book, small enough to be put into one's pocket.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. small enough to be carried in a garment pocket
Word Usage
"A price range of 350-400 and a "pocketable" size seemed reasonable to me, but then I realized that cameras falling in this range left me wanting more, so I've given up a bit in these constraints."