Leather-Bound

Over on my other blog, I titled a post "Hell-Bent For Leather". (It's about, of course, leather scents.) When I thought of that title, it occurred to me that "hell-bent for leather" doesn't make a molecule of sense.

Not that it has to, of course. There are plenty of idioms that on the face of them don't. But "hell-bent" means "bent on going to (which is to say determined to go to) hell". Where does leather enter into the picture?

As it turns out, the phrase is a mashing-together of two expressions; "hell-bent" and "hell for leather", which means "really fast", the leather referring to the saddle on a horse. Even that is an odd expression, but at least you can see that it makes a kind of sense.