I'm a computing engineer with a solid background in mathematics (or at least it used to be so few years ago): i've no problem with calculus, derivatives, probability and so on — but i really have few clues about stock trading, options, accounting principles, NPV etc.
Every book i found about financial mathematics or the like seems to concentrate be on the economist's side — e.g. they try to explain with great detail and care calculus or probability concepts, which to me is a no-brainer — while giving few clues about what's behind it (e.g. why math is used that way in a particular context).
Can someone direct me to good introductory books to financial and economical mathematics from "the mathematician point of view"?