"What's in the bag?"
A sturdy, 12oz-cotton-canvas tote measuring H13" x W18" x D6". Gusseted for added strength, it can hold between 8 and 12 hardbacks (that is, if it did contain books, which it certainly does not) or a frankly absurd number of paperbacks.
Reassure your worried family members who are "just concerned that you might be hoarding" and wonder "why won't stop reading while you're driving, it's incredibly dangerous." I don't know anything about the second thing but you're totally not hoarding because there are no books in the tote.