To achieve its platonic ideal, a travel mug needs to succeed in four areas: 1) it has to be easy to carry around and drink from; 2) it has to keep liquid piping hot (or bracingly cold) as long as possible; 3) it has to be leak proof; and 4) it has to be easy to clean. Failure in any one of these areas relegates it to that semi-disposable state where it's either shoved to the back of the cupboard or indifferently abandoned post-drink and mid-travel. I've gone through a lot of mugs, but I think I've finally found a keeper: the Zojirushi stainless mug. It looks (and acts) more like a thermos, and except for its size (it comes in 12 or 16 oz.) and the lid (a handy flip-top number with a well-designed drinking spout) that's just what it is—which means that it keeps drinks hot for hours. On a recent test run the coffee I made at 8:30 A.M. was just as hot at noon when I had my last sip. The mug fits neatly in a cup holder or a large coat pocket (the 12-oz. size, anyway) and the lid's locking system makes it a breeze to open and close with one hand while ensuring that you can also drop it into a bag or pocket and it will never, ever spill. That's pretty impressive. Best of all, the body is stainless steel and the lid comes almost completely apart. So while you can't put it in the dishwasher, it's a snap to clean out with a bottle brush. And for a travel mug this good, it's worth the small effort.