They do, actually, if I'm not mistaken. They just have the nasty side-effect of aging you up, as soon as you try and go back to the present, meaning your ass is staying in the past, within an alternate timeline, if you use it, unless you want to be gaining several centuries, and become a skeleton in the process. And given how dumb the wizards can be, odds on them finding a library worth of not to their venture are slim at best. :jordangif