Where do you take your books?

So here's an article that I found sadly amusing today: Going to the Emergency Room? Bring a Book. It's especially apropros for me this week; my husband ended up in the emergency room in Las Vegas for a locked-up back( really, that's all it was; he's as straight an arrow as you'll find) and I winged it down there to make sure he was okay. I didn't have to go to the emergency room itself-he'd been discharged. But even as I frantically called work, his mom, all the obligations I had that day to make arrangements for a replacement (it happened to be the day that T.C. Boyle was doing his big event), packed and made it to the airport within an hour, I made sure to pack a couple of books. Once I was on that airplane, my book kept me calm and distracted instead of worried and fretting.
If I had gone to the ER I would have had a book in my purse. I always keep several books in my car, just in case I've got to wait somewhere for awhile, or end up eating out alone. Without a book as a backup plan, I feel naked. I remember one plane flight when I absent-mindedly checked my bag, forgetting that my book was stashed in it. Panic! By the way, those airport bookstores do NOT have much in the way of selection. They stock the bestsellers, sure, but I usually want something a bit more offbeat, being pretty familiar with the usual top ten stuff. I picked a book from the airport bookstore nevertheless, an author I hadn't tried but thought I might like and should at least know more about, and was disappointed.
I guess the feelings of panic that I get without a book should disturb me, but they don't. Books comfort and soothe me, and let me slow down my brain and distract myself from the myriad of things that can cause stress during the day. Some people like TV, some people like drugs, some people like food, I like books. (Well, food's not so bad either; hence my cookbook addiction.)
The longer waits in the emergency room described in that article worry me too, but that's a whole different kettle of fish and probably not an opinion you're interested in.

Where do you take your books? How have you used them to comfort yourself?