If you are a student just taken up a course in derivatives or risk management you should have this book. if you find john hull more technical, you have Don Chance who covers options and other derivatives in a greater detail and in more words. everything you want to know about how banks etc have risk mangaement systems in place and market risk instruments is here.
in case you want a greater coverage of options and pricing options, you should definatly take a look at Black Scholes and Beyond by Neil Chriss, a work of art.