Hello Professor Mankiw.
I am an Engineering student at Rutgers University. I have taken Intro to Microeconomics and am about to finish Intro to Macroeconomics, both courses using your 4ed books of those subjects. I would just like to tell you that your books are simply amazing. You explain all the theories and definitions of economics very well and I rarely would have to double check outside sources for help. Reading your books have gotten me very interested in Economics and I have decided to minor in it (sorry not majoring, but the engineering curriculum is so demanding that there isn't even space for a minor!) These books are great, and I will most definitely use them for help if I need to go back to Economics 101 in my more advance courses. Great work!