Merck is a terrific resource guide to have in your pocket for a quick refresher on the most common medical conditions. Not only are sections clearly laid out, but all essential info are condensed into user friendly tabs. This is essentially a quick and dirty but much easier to follow alternative to up to date. Such a wonderful and surprisingly free resource should not be missed! Be patient and leave the app on the first time around for it to fully download (takes about 20-30min... It looks stuck but its really not).