For those folks living/working in remote parts of the world or those preparing for the end-of-the-world, one of the best medical books for a novice that I have found is the “Where there is no doctor” series by the Hesperian group. They offer all their books as free downloads but of course, when there is no power or puter around, having a bunch of nifty e-books on your flashdrive is pretty useless. Here is the link: http://www.hesperian.org/publications_download.php.
Not meant to advocate everbody DIY their medical needs. If you live in most places in the USA, dial 911 or go see your doctor. I’m a paramedic and have seen what happens when people try to medicate themselves without knowing that they are doing.
However, if you live 3 hours from the nearest hospital or spend a good bit of your time in 3rd world countries like I do, these books are an excellent tool to have with you.