Mark Russinovich is a windows Ninja and he has been for a long time.  He is bona fide.   This does not mean that he is necessarily able to write a good novel, develop characters, or articulate convincing scenarios about cyber-terrorism. Fortunately, he is able to do all three. Zero Day was fun to read, intense thriller.  The technical side of the plot was great.  No surprise here, but the larger plot was believable and more than a little scary.  This was a good read for both quiet technical and not so technical readers.